As others pointed out, having the feeling of knowing (about) things without actually having experienced them yourself is a core feature of what one might call intelligence, and as such not insane.

I would argue instead that the problem isn’t with arguments over stuff you haven’t experienced yourself, but rather people caring too much about their fixed opinion and not about actually trying to find the truth (e.g. though argument) as they might proclaim.

(I am relatively certain of this point as I’ve seen seemingly good counter examples to this provided by the LessWrong community, where people often discuss topics they do not necessarily have experience with, but rather try to find the truth and therefore not have a fixed opinion beforehand.)