This is the wrong sub to ask. And whatever the law says, take it with a grain of salt. There's still more context. The thing you're looking for are "fighting words". Fighting words might defend you when called to stand for what you've done, but they don't justify anything. Not legally. No one is encouraged to fight.

Bottom line, usually, is that you're responsible for your own actions. You can't batter someone just because they said you were fugly. You might get away with it if they screamed the n-word at you. But these aren't hard-and-fast rules, so the general rule is, don't fight.