Being embarrassed about your knowledge is anathema to rational conversation. You can see it in drug policy debates, where nobody talks about how relatively harmless marijuana is, for fear that people might know that they smoke it. You can see it in censorship debates, where no community member is going to stand up and say "hey, this porno doesn't violate my standards, in fact it's pretty hot". We can stand around pretending to be good people, or we can get at the truth.

You sound like you're advocating radical honesty. It seems like there should be a middle ground of making sure relevant information is introduced, but doing it in a way that minimizes derailing self-disclosure (or self-disclosure that could cost you in status).

Also, arguing from personal experience can be form of defection, shifting the conversation to an arena where one's convincingness is proportional to one's willingness to lie. (I think I have some comments saved that say that better than I can.)