Gregory Rodriguez has an excellent article in the Los Angeles Times about the nature of conspiracy theories and why people believe them.
The real truth is that, as weird as they are, rumors and conspiracy theories can only thrive in the minds of people who are predisposed to believe them. Successful propagators of fringe theories don’t just send random balloons into the atmosphere. Rather, they tap into the preexisting beliefs and biases of their target audiences.
Plenty of studies have shown that people don’t process information in a neutral way — “biased assimilation” they call it. In other words, rather than our opinions being forged by whatever information we have available, they tend to be constructed by our wants and needs. With all their might, our minds try to reduce cognitive dissonance — that queasy feeling you get when you are confronted by contradictory ideas simultaneously. Therefore, we tend to reject theories and rumors — and facts and truths — that challenge our worldview and embrace those that affirm it.
This is likely true for every one of us, myself included. I find myself jumping on the bandwagon with news and stories that fit my world picture but I usually realize that I am not letting my well learned skepticism kick in and soon get it sorted out. Granted I still get fooled now and again but not often. This most recent period in American politics has done a fairly good job of sucking the 'pollyanna' out of my world view. Yes, I still get excited and believe at times that there is light at the end of the tunnel and I guess that will always be the case as I am not ready to give up life without some hope and I will always believe the positive attributes of our world will come to bear eventually. And yes, I understand "The Two Hands of God" bit and all the other yin and yang stuff.
What else is apparent is the "right" is pretty much gone over the edge and nothing like facts and logic is going to drag them back from fantasy land. Over the last 8 or 10 years, surrounded as I am with the hard right, I have come to realize that they are just too far gone and wrapped in their fantasy world and that reason and logic are no longer an effective tool for communication. No scientific fact or even the evidence in front of their eyes is going to change their minds about whatever bizarre notions they have about the world around them. It's not worth the effort to try and talk with them. I still try and reach out to the somewhat 'sane' but have effectively given up on the 'land of the lost'.
From the Buddhist perspective of "your outer reality is a projection of your inner reality" we have a serious problem with a rather large piece of the American public. I would have to say that there are way too many people running around with a very twisted inner reality and that is one disturbing thing to contemplate. I'm just saying.