To me it is only evidence that people are irrational.
The issue is: How do you know that you aren't just as irrational as them?
My personal answer:
I'm smart. They're not (IQ test, SAT, or a million other evidences). Even though high intelligence doesn't at all cause rationality, in my experience judging others it's so correlated as to nearly be a prerequisite.
I care a lot (but not too much) about consistency under the best / most rational reflection I'm capable of. Whenever this would conflict with people liking me, I know how to keep a secret. They don't make such strong claims of valuing rationality. Maybe others are secretly rational, but I doubt it. In the circles I move in
r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.