If you were upset or concerned by the behavior, it would be worthwhile contacting the police. However, there is a very good chance that no charges would ultimatley be pressed, or, if pressed, would then be sustained.  That's because there is no requirement for people to be civil or polite in any way; someone is literally allowed, in a public area, to swear or yell at you as much as they'd like. Only if there was something about the situation or behavior that transcended it and suggested an immanent threat might there be grounds for charges. Of course, there might also be grounds for an involuntary committal, if someone is acting sufficient irrational in public, so that is another reason, besides the possibility of criminal charges, that it would be worthwhile calling the police if the behavior is so far beyond the pale of normal behavior as to suggest mental dysfunction as well as a possible threat.