They don’t care about anyone else. They believe that they shouldn’t care because other people do that crap, and/or if someone is annoying they should block it out with headphones. Asking them to keep to themselves is worse than just blocking it out in their eyes. I cut ties with people like that. “My” mother is like that, blasting stupid duolingo games in public areas. Bitch did that for a whole train ride and also in the elevator, and found it Funny™ that I asked her not to do that.

Short answer: they don’t care and are most likely marijuana addicts who beat their significant other when they withdraw and/or are emotionally abusive. Incredibly red flag.