I like Dalrymple and here is one of my favorite quotes;

In my studies of communist societies, I came to the conclusion that the purpose of communist propaganda was not to persuade or convince, not to inform but to humiliate; and therefore, the less it corresponded to reality the better. When people are forced to remain silent when they are being told the most obvious lies, or even worse when they are forced to repeat lies themselves, they lose once and for all their sense of probity. To assent to obvious lies is ...in some small way to become evil oneself. One's standing to resist anything is thus eroded, and even destroyed. A variety of emasculated liars is easy to control. I think if you examine political correctness, it has the same effect and is intended to.

His comments against witchcraft mania, etc. is the same. He makes some good observation but fails to draw out the implications. As his witchcraft example shows, evil is the master at psychological manipulation (MKUltra anyone?) to whip people into a frenzy and achieve their evil ends. But what about the good guys? What do we need to do to protect ourselves and our children from such tricks? To me that is the key question.

He only hints at the answer when he writes "To assent to obvious lies is ...in some small way to become evil oneself." So the question really boils down to if good people can be 100% honest or not. There is an old expression in the con artist world that you can't con an honest man. It is really that simple but everyone seems to like cutting a few corners and "become [a little] evil oneself".