The vast majority of people are emotional, not rational. Not that I agree with Xant's retarded holocaust-denialist bullshit. The same morons who to this day are convinced 9/11 was an inside job parrot the same thing. Or people like Alex Jones. "I'm an intelligent individual, unlike THOSE SHEEPLE *SNEER*". It gives idiots carte blanche to legitimize any conspiracy theory bullshit when they are convinced they are part of a small elite that can actually see the "truth".
Xant, what are your sources for your assertions? Don't tell me to read a book by some ridiculous crackpot, give me actual sources, that contradict literally every single historical analysis of WW2 (based on the hundreds, thousands of government records recovered at the end of the war. The chocolate chip cookies were methodical in documenting everything).
That being said, by definition, at least half of any given population have an IQ below 100, i.e below average. There might be higher concentrations on either end of the spectrum, but that's what it averages out to. It doesn't mean higher IQ people are necessarily better critical thinkers or are immune to emotional justifications. Because they aren't.