Was it an isolated incident, or was it part of a larger pattern of unsportsmanlike behavior?
If it was an isolated incident, I think you did the right thing in asking the coach to handle his own internal situation. Throwing a flag on them for infighting is likely to misplace attention, anger, and blame on you--you're just adding fuel to the fire.
But if it's part of a pattern of behavior and control of the game is in doubt, USC and DQ may be appropriate. Good judgment is required.