Hi PoO and my apology for only responding specifically to only one paragraph.
That's all right.
Been a while since I looked but I think even wiki divides atheism into about 6 groupings. And it may well be that I most accurately slot into the 'agnostic' side of the spectrum. Yet that agnosticism is not necessarily a concession to religious style belief.
It may divide it into groupings, but from what I read, it is a debate about whether or not these things are atheism or not. That is, some people argue that agnositicism is "weak atheism," but that's an argument that seems to be kind of pointless. If there are several quite different stances/beliefs on the existence of deity/God and soul/spirit, then why would one lump them into a bigger term that is relatively useless as a distinction? From the point of view of someone interested in human society, cognition, and religion, that is like the term "plant" for a botanist. It just isn't very descriptive if there is little unity among the adherents. A person who believes in a universal energy but not a personal deity, for example, is still very different from a person who is a total materialist.
In some ways, that is what I feel about the term Christianity. But at least in that case, Christ's teachings are unifying a very diverse lot. There seems to be no equivalent unifying factor in these different "forms" of atheism, so why not just have a term for each type?
The puzzle analogy is perfect here. Sometimes doing a jigsaw puzzle a piece will jump out at you and you will know exactly where it fits into the big picture. Yet a single tounged piece will never fit into a space with 4 tounges.
But with the spiritual world, arguably we are creating our pieces through our own interpretations. This is all stuff that is only individually experienced. It isn't like piecing together the evolutionary tree or something. So I fail to see how it can be approached in that way, or how we can fail to acknowledge that we're all pretty much doing the same thing- inaccurately concluding stuff based on a realm we can only partially approach. Whether it exists or not is a mute point, as no one can ever prove or disprove it. What is a better question, in my opinion, is how one's belief system and spiritual experiences impact one's own life.
To me religions, spiritual beliefs or whatever attempt to say they are the whole picture or their god is or created the whole picture.
Not all religions do this. To limit it this way is to deny religious diversity. Some religions, such as Buddhism, say the exact opposite and others, such as many animistic/shamanic systems, don't focus on the "whole picture" at all, preferring a localized approach.
They are the product of human mind, culture and history and deal with that and not the wider nature of the reality I find so captivating. If you are always relating your view of reality through the crude glass of a single, however complex, lense you are only going to get the image of what that lense was self manufactured to 'correct' to.
All humans see reality through a crude lens. It is part of the human condition. We are culturally conditioned. We can choose to be aware of this conditioning, though. Relegating such conditioning to "religion" and not acknowledging that this happens regardless of one's religious beliefs is false.
Every 'believer' is a religion of one. Each has their own idioscyncratic interpretation whether they be like you or one that hangs their whole being on a narrow interpretation of a single book. There is a different lense for every one of us. If there were only two believers left alive there would still be two gods being proclaimed the real one. When someone says they understand it all they want you to know their interpretation.
That is true of every aspect of human social life. It is also how culture works. No group is a group of uniform individuals. The real question, as an anthropologist, is what holds a group together given our inherent individuality. That's a much more interesting question to me. What forms belonging, community? What forms our sense of identity?
Our religions are overwhelmingly regional and tribal.
Really? I don't think Buddhism is much like that, and it is the religion of a fairly large group of people. Again, we shouldn't limit our views of religion in such conversation to the Western ones.
The emergence of advanced cognition was an adaptive evolutionary advantage, it evolved, it was not 'bestowed'. We can observe its emergence in other species including monkeys, primates, birds and several other land and marine mamillian animals. And even some invertebrate species have highly complex language for a communual purpose so altrustic it would put any Christian or Marxist to shame! Do we want to proseltyse to the Bees? (No, we just target their Queen

) Teach our captive bred parrots to say 'amen' ?, (has to have happened many times already

).
So what is your point? I don't need to believe humans are different from other beings, or were created uniquely, to have a spiritual life. In fact, in many animistic systems, other beings are seen as having societies, powers, sentience, etc. just as humans are. I fail to see how evolution proves or disproves anything?
When I think about how humanity fits into the picture I first have to understand how humanity evolved yes, but more than that I have to be able to relate it 'dispassionately'. Someone looking always through a lense of inevitabley flawed and self unique belief cannot do that. And this is why I say I have no belief, that my atheism is not a belief but an absence of one.
I am highly skeptical that anyone can exist without a lense of "flawed and self unique belief." Sorry, but I would say you have this just as much as me or anyone. It is part of being human. We exist with cultural conditioning, and you exhibit yours through your assumptions behind your statements about "religion" in general, when you are mostly talking about Western world religions. I also don't see how being dispassionate about things is necessary. This also tracks to a Western scientific worldview that values a lack of emotional investment in one's inquiry. But why is that more valuable as a worldview than others?
But accepting repeatable scientific observations is not a religion. It is just plain common sense. No matter how some would twist it to be something else. And with science you can look at, if not answer, everything and anything.
First, scientific observation only works for certain things- observable things. Spiritual experience is necessarily individually and broadly understood as transcendent of material life, so I fail to see how Western science has jurisdiction. Most scientists I have met agree with me. That is why the university places the study of religion in the humanities, and in the social sciences, it is studied as a social institution but not as a "proof/disproof." Such studies would be pointless and largely laughable. Sicence is not something that answers everything. It is one form of inquiry and knowing among many, and that is why the entire university is not the school of science, but we also have other schools- the humanities, the arts, the social sciences.
A total unbending in this indicates a faith in science that most scientists do not have, a faith that approaches religious belief in that it is unjustified.
For good science though, clear sight is a must.
I think postmodern critiques tackle this pretty well. I would suggest reading some. "Clear sight" is nearly impossible, if not entirely so. A good scientist will recognize this and work toward acknowledging and understanding their own obstructions so that their inquiries are done honestly. But no one can ever get rid of their own assumptions. We just replace some with others.
Anthropology is a science with many unkowns and unknowables. The data you work with is inevitably fragmentary. A lot of it is little more than, as far is actually possible guesswork, educated guesswork.
That sounds like many, if not all, of the sciences. I recently had a discussion with an astrophysicist who talked about this with me.
Furthermore, as religion falls under "how people think" not "how the world works," I would say it is outside the boundaries of what the natural sciences can effectively study. If the Divine exists, then religion or the spiritual life is the intersection of something beyond the observable/experimentable world with the human soul/spirit. That is clearly outside the boundaries of natural science. If the Divine does not exist, then religion or the spiritual life is inside the human mind and the cultural life, which we already know cannot be reduced to mere biological factors by its emergent nature. So again, it would seem we need to turn to other methods of inquiry.
It will make little definitive difference outside of a very localised context.
How can you prove or justify this statement? If this were true, no one would try to theorize or generalize about society or culture, about the human mind, and so forth. That anthropologists have always done so and continue to do so contradicts your statement. No offense, but I fail to see how someone has the right to define a scientific field and its boundaries for the scientists involved in it?
Every question leads to only more. Sometimes a few pieces show something, othertimes you are able to connect one piece to another. But they never are the whole. And for me it would simply feel dishonest to say I could even guess at what reality is.
Isn't that the point of science? Science isn't about finding the answers, but about becoming aware of the next set of questions. That is the drive behind scientific inquiry.
But I can see what religious and superstitious belief is. And I see it as a self crafted myopic lense. As I shall explain in my reply to Dondi....
I think such a statement indicates the self-crafted lense of the person who says it more than can encapsulate the breadth and depth of religious diversity in the world.
I'm sorry to say, such a view is crude by both humanities and scientific standards. You criticize religion for making sweeping generalizations, unfounded assumptions, and overrunning the diversity of human thought... yet you do the same.

The only way out, in my opinion, is to be honest with oneself and say "I do not know what is beyond my own life experience, and my own observations are interpreted through my own limitations- in personality, in intelligence, in learning style, in cultural worldview." This is honest. It does not priviledge onself over others.