The refs had called some fouls due to physical play leading up to that play.

I think that while you're right - the refs can make calls and that help control the game - it's also a great idea to warn the coaches that things are heating up and there will be consequences to their players.

It isn't necessarily up to the coaches to control things. But I bet they want to know if that's on the refs mind before the refs start tossing players and they are left to play the game with fewer guys to play.