Most Muslims I've met would never dream of killing anyone over an insult but when you ask them about the cartoons of the Prophet you can see them visibly bristle. For the majority of Muslims it's simply a line people shouldn't cross. Does it require murder? Of course not, it requires suing the paper out of existence.
If you are a religion, I doubt the values of that religion would be sufficient grounds to sue when you've been the subject of satirical representation.
If you are a Hollywood celebrity, different matter. That says something about our culture, I think.
As for not hearing Muslim voices speaking out about such things, did you see the marches in Arab countries against 9/11? There were plenty of them and very big ones (the one in Tehran was massive) but they never made it to our media. Have you read all the scholars and Imams speaking out against ISIS? Probably not because our media doesn't cover it, yet I have because of the papers and websites I read.
I saw Muslim leaders speaking out against the Charlie Hebdo attack. I looked for repeat coverage in the media later. Nothing. Everyone else was getting their opinion aired over and over.
I think Islam's in a no-win situation here. I used to get annoyed with the voice of moderate and sensible Islam not speaking up, but then I discovered it does, it's just no-one's listening. And furthermore, just look at what the media does say, usually reflecting and reinforcing the values of the uninformed.
One final point if I may, just because we in the west decided there are no limits, you can say what you want, take the mickey out of whoever you want doesn't mean the rest of the world has to agree with us and go along. Muslims have said very clearly there is a red line people shouldn't cross and the western world has said 'yeah whatever' ... we (the western world) don't rule the whole world, we don't get to decide for the whole world and at some point we need to understand that.
A very good point. This 'anything goes' mindset is a signature of cultures in decline. There's actually profound explanations for it in esoteric and occult circles... I suppose the question coming back is, "Is nothing sacred?" to which the glib answer is "No". Until, of course, one's 'personal rights' are infringed.
Has anyone asked the question: "What is the problem with the West that causes such things as militant Islam?" It certainly didn't arise in a vacuum. ISIS is as much a product of the west, if not more, than it is of Islam.