I live in a big metro area but I drive everywhere, don’t use public transit .

I do travel to big cities, some cities often. And use busy public transportation, think NYC, Chicago, London, Paris, Moscow.

I don’t see any difference between how people behave on a public transportation in the US versus other countries. I don’t see US public transport being less safe and why would it be?

Usually it’s a luxury to choose wher to sit on public transport in
any decent size city. Sometimes you lucky you have place to stand! Most people don’t think of public transit as social time or place to meet others, more just way to get to work or school and home