There’s a big difference between self-assessed qualifications, and ability to admit fallibility. Good scientists know they know a lot. Great scientists know that they don’t know a lot, and admitting that you might be wrong is critical for the scientific method to work.

So DJB is brilliant, but if he admitted that he could make mistakes (or even that a compiled could mis-compile his flawless code), then he might have put in failsafes like unreachable code assertions that would have meant that we wouldn’t be discussing this today.

I don’t think he’s a jerk. I don’t know enough about him; maybe he’s the nicest, kindest guy around. I do think the evidence suggests that he’s arrogant, though, and that’s not a good look on anyone.