There are different "trains of thought" on repeating. One school says by making him repeat what he said, it gives the coach an opportunity to rethink what he said because it's clearly an ejectionable offense. Think of it like a parent/child relationship. "mom, I hate you" "What did you say?" "Nothing".
The other school says just dump him. It depends on the level and what your supervisor wants. In pro ball, its an automatic EJ. HS, maybe. Youth, it depends on the coach and the situation. Some of them REALLY dont know whats acceptable and what's not.
Another alternative might be to respond with "you know you can't do/say that, right?" Again, it puts the onus on the coach to try it again or just walk away.