“Heckling is a part of the game. And the opposing team’s fans know it bothers him. If it bothers him it can effect his game.”
It’s called having rabbit ears. Heckling is probably as old as organized sports. Once the opposition finds they can rattle you with it, you’re done for.
Well then, you should not have gone pro.
They don’t call them foot ball hooligans for nothing.
They go to the games to get drunk and get rowdy.
A law telling them to be nice is not going to change them.