please help me figure out where the goalposts are
The goalposts in which particular game? This has grown from talking about a minor mistaken view into a request for general guidance on how to evaluate people's reputations and claims about truth. If you're looking for help with epistemic rationality, well, I heard that there is a whole forum concerned with it and trying to be less wrong...
And unless you're willing to accept me personally as the Ultimate Arbiter Of All Things, I don't see why my opinion about some girls in some videos (which I haven't looked at, by the way) matters.
The goalposts in which particular game?
No game at all, I am simply scrutinizing your statement "that looks to be a strawman."
This has grown from talking about a minor mistaken view into a request for general guidance on how to evaluate people's reputations and claims about truth
Not at all, I am trying to nail down your position.
And unless you're willing to accept me personally as the Ultimate Arbiter Of All Things, I don't see why my opinion about some girls in some videos (which I haven't looked at, by the way) matters
I am asking f...
What is something you used to believe, preferably something concrete with direct or implied predictions, that you now know was dead wrong. Was your belief rational given what you knew and could know back then, or was it irrational, and why?
Edit: I feel like some of these are getting a bit glib and political. Please try to explain what false assumptions or biases were underlying your beliefs - be introspective - this is LW after all.