OK. But these people do not make researches or readings about what experts say on some subject and decide according to that. They are opinions and ideas are not really built. They only listen what few people in their circle says, whoever in the most powerful position and repeat that to each other and others to have a standing, to be accepted in that group. Religious, nationalist groups are closed groups with strong hierarchies by thier nature and definition. They are not tolerant, diverse groups.
If you join one of these groups and ask them to explain their beliefs, nobody would try to explain something but hand you some source telling what it is the truth and that it is the truth. Chances are high that you won't have conversations and probably won't last long if you insist and at some point, you'll be told to leave. You would even be in danger of some sort.
If you join some tolerant, diverse, democratic group in general and try to argue about conspiracy theories, people would argue back with different ways, styles, sources, books and at most laugh at you some point, if you insist on it.
Also, I've missed this one somehow: "...airplane GPS is rigged to fool pilots into thinking otherwise. ..." LOL