You make it sound like it's an absolute warzone (your demographic certainly likes to push that narrative even in the most uneventful of places!). Yes I've taken trains back home from nights out at 4:30 in the morning where there were drunk girls talking loudly and (gasp!) trash on the floor. There's certainly no-one "blasting loud music" in the average train and definitely not "doing drugs".

Ofc there's a non-zero number of crazies, violent people, sexual harassers, etc. That's a certainty in a system with 400 million trips a year! But then please don't leave your home, there can be an ax murderer lying in wait at any corner!