To me it is a faith-induced form of ignorance - that because you have mastered one of the tiny, tiny subsets of all the world's technical knowledge, you believe yourself to have similar ability in other realms of knowledge as well. Morality and ability become one and the same, especially after the conditioning of hundreds or thousands of pissing matches in which you attempt to prove the same point, over and over: "I'm right and you're wrong." Logic becomes one's drug, because it lets you win and be powerful. Other flaws don't matter because you can avoid those discussions(if you're a white, straight cis male).
But really, it's relatively easy to find people who know a lot of things and can work through deep logic. "Big-picture" judgment and perspective is a lot harder to come by.
Because only stupid people are sexist and racist. We are smart, ergo, we cannot be sexist or racist.