Thee are horrible things done in the names of all religions (including atheism). Human beings are like that. We use whatever we have to hand to hurt other people, when that is what we want to do. People seeking advantage or vengeance, mobs, rulers seeking scapegoats...

But it just is not true that "Moslems have a duty not to spread their faith by converting...but by killing those of other (infidel) or no faith". That's what Jews call a "blood libel." It feeds into hatred and fear. It's thye kind of think that was said by murderous "ethnic cleansers" in Bosnia and Kosovo. And it is not true.