I've read an Orthodox person say reform Jews are not real jews before.
This isn't consistent with my understanding of what makes someone halachically Jewish (if I even have that word right) but what it does sound like at best is an intra-religious debate that neither you nor I are fully qualified to comment on with any authority.
Anybody can become a "Satanist" that is join one of "Satanism's" various branches. I'm sure people from many religious backgrounds do.
But that doesn't mean it makes sense to conflate one religion for the other.
I am not completely sure I follow how you conflate following Satanism with being a demon. I am not sure it's quite the same thing. It would help if you would clarify your definition of what is Satanic and what is demonic. People know the terms, but we need to know what definition you are going by.
As to Sabathai Zevi --that again is an intra-religious debate about Messianic claims and conversion out of the religion.
I don't think we have enough facts on demons to make too many assertions on trying to identify human groups or individuals as demons.
Your statement about the Golem being "brainwashed" does not make any sense to me. My limited understanding of Golem is that they do not have wills of their own and of course are made out of clay, that's what a golem is. I don't know if you are referring to the story about the golem and the Jews of Prague. I don't know a whole lot about that other than in passing.
If you are somehow trying to say that because Judaism has a mystical tradition and the Zohar and Kabbalah and also folklore about things like golem etc -- if you are distorting that into saying they are into "Satanism" or
being demons or anything else -- yeesh.
That would be right next door to saying anything with mysticism is demonic. There are traditions all over the world that have mysticism traditions or esoteric traditions or even supposed magic. New Age material touches on esoteric matters.
I hope you're not conflating mystical and esoteric traditions with Satanism. Or any of that with being a demon.
I hope you're not going to accuse either everyone, or any particular religion, of being either Satanic or demonic.