You highlighted "ideology." I think ideology (vs pragmatism, empiricism, etc) is one of the worst obstacles to human progress.

Granted, it's a product of "stupidity [and] ignorance" but even relatively thoughtful and informed people can fall prey to ideology, a sin of over-generalization.

P. J. O’Rourke was great! From your "P.J." in the title and the first few sentences, I recognized it as him. I remember seeing him on Bill Maher -- one of his more interesting and enjoyable guests.