IRL what doing you mean by "training" here?

will largely be dependent on what they have been (actively OR passively) trained to do

You are being trained 24/7 by forces often completely out of your purview. Every interaction is molding your behavior behind the scenes; From things as subtle as a half smile by a total stranger to something as blatant as a billboard telling you you're not a real [insert gender here] unless you use X Product. We call it Classical Conditioning and I very much recommend reading up on it quite a bit before declaring blanket statements about human behavior.

When they enter adulthood they're expected to expand on that base knowledge on their own, and we often judge them if they pursue garbage sources and come to garbage conclusions in doing so.

All those judgements are still subjective, and the people you are judging are often judging right back. Let's be real, if you would like to get all judgmental perhaps you should be asking yourself why we're wasting time on a shitposting website while the world burns instead of doing actual work towards revolutionary action. This site is very much not an endpoint for leftism, it's a speedbump. There are like a relative handful of people on this site doing revolutionary work while the rest of us cosplay as leftists, accomplishing just as little as any other lib.