It depends on which conspiracy theories you mean. I probably agree with Snowden on his last point that people make an identity out of which conspiracy theory they believe. Groups base their membership on which conspiracies are believed. I just always felt that way so he didn't give me that idea.

I wonder if we label the irrational or maybe unverifiable beliefs of unfavorable groups as conspiracy theories but we label similarly unverifiable beliefs in a conspiracy as 'lived experiences' or 'perspectives' when they likewise have no evidence. The only difference in how we treat the beliefs is based on the racial/religious/political preferential status of the group that has the beliefs.

So conspiracy theories are probably pretty common and uniform and not confined to certain groups.