Oh, I think that goes without saying. Yes, obviously more pragmatic grievances rooted in the public’s direct exposure to social problems will have a far greater effect on their values and behavior. But I just wanted to point out that metaphysical beliefs aren’t completely impotent in this regard. They still play some roll.
As for the clergy not calling for war and violence, I know for fact that there are cases in which certain religious leaders deliberately take passages from the Quran completely out of context for the sole purpose of brainwashing followers. For example, they will quote the passage
without also quoting the very next line which says
Al-Anfal 8:61-62
It also comes to mind that a large part of the motivation driving suicide bombers and those who crash planes into buildings is the metaphysical belief that they will be rewarded for their acts in an afterlife with 70 virgin women. I don’t believe the motivation would be half as powerful if all they believed about death was that it was the end of conscious experience forever.
Even if this is a bad example overall, I think my point still stands - that metaphysical beliefs can have significant effects on people’s values and behavior, and in this respect they can be useful (if put towards positive ends).