According to Goleman, our heuristic thinking can be seen as "the low path" while our critical thinking can be regarded as "the high path". Both paths are useful, since sometimes there is simply not enough time to process "the high path" and we must act according to our "low path", which is still way better than making random mindless decisions.

Honestly, I don't know if the (((really, really dumb))) conspiracy theories such as the one you described are based on the lack of critical thinking, or on the need of some people to try to present themselves as smarter than other at all costs. Some people just don't like anything mainstream and always tend to speak something else, even if it's mindless. I just can't believe that some people have so low critical thinking ability that that is the reason for them to believe in the missile theory or the flat earth...

Cheers!