Usually if you violate social norms people just push you out of the group and not bother explaining it to you. Not always, but usually. Yes if it is so bad it gets violent or something you will find out for sure why, but if you just show up to a friend function and start spouting off about gassing the jews or something most likely people just won't invite you back and never explain why.

Actually finding out why you were violating social norms I've found is mainly found either on the internet or from your parents when young. Hardly anyone in real life is going to bother telling you why, especially when some people are liable to act violently and there is no upside to them for bothering to explain it to you.