We are arguing different things. I have never stated "psychological effects of the Internet aren't real and therefore this discussion is moot." My argument is "psychological effects or not (and personally I think they are overplayed), the privacy tradeoff of trying to fix them is not worth it (and I doubt any vague gestures in the direction of age assurance would help)." You are focusing on the first parenthetical but the important part is outside it.

We also have no way to actually measure this even if we wanted to do an experiment. So comparing this very soft science to climate change is a bit out of pocket.