They believe what they are saying because they get paid for it. And because they get paid for it and the "extremists" don't get paid for "extreme" opinions, this is "market validation" of their opinion, hence making them correct in saying it again and again, for which they will get paid again and again, and hence validated again and again. The physical realities of the universe don't even register with these people. They live in an artificially created fish pond of dollars. Until those dollars dry up and blow away, they will refuse to look outside their pond.