What you seem to be saying, that I agree with, is that it's irritating as well as irrelevant when people try to pull authority on you, using "age" or "quantity of experience" as a proxy for authority. Yes, argument does screen off authority. But that's no reason to knock "life experience".

If opinions are not based on "personal experience", what can they possibly be based on? Reading a book is a personal experience. Arguing an issue with someone (and changing your mind) is a personal experience. Learning anything is a personal experience, which (unless you're too good at compartmentalizing) colors your other beliefs.

Perhaps the issue is with your thinking that "demolishing someone's argument" is a worthwhile instrumental goal in pursuit of truth. A more fruitful goal is to repair your interlocutor's argument, to acknowledge how their personal experience has led them to having whatever beliefs they have, and expose symmetrically what elements in your own experience lead you to different views.

Anecdotes are evidence, even though they can be weak evidence. They can be strong evidence too. For instance, having read this comment after I read the commenter's original report of his experience as an isolated individual, I'd be more inclined to lend credence to the "stealth blimp" theory. I would have dismissed that theory on the basis of reading the Wikipedia page alone or hearing the anecdote along, but I have a low prior probability for someone on LessWrong arranging to seem as if he looked up news reports after first making a honest disclosure to other people interested in truth-seeking.

It seems inconsistent on your part to start off with a rant about "anecdotes", and then make a strong, absolute claimed based solely on "the Sokal affair" - which at the scale of scientific institutions is anecdotal.

I think you're trying to make two distinct points and getting them mixed up, and as a result not getting either point across. One of these points I believe needs to be moderated - the one where you say "personal experiences aren't evidence" - because they are evidence; the other is where you say "people who speak with too much confidence are more likely to be wrong, including a) people older than you, b) some academics, but not necessarily the academic consensus".

That is perhaps a third point - just why you think that "the process of peer-reviewed scientific inquiry, informed by logic, statistics, and regression analysis, offers a better chance at discovering truth than any other institution in history". That's a strong claim subject to the conjunction fallacy: are each of peer review, logic, statistics and regression analysis necessary elements of what makes scientific inquiry our best chance at discovering truth? Are they sufficient elements to be that best chance?