Might actually be a legit rule. A player or coach gets kicked out for fighting, you don’t want them back on the floor trying to start something up again. People get stupid when they get hot headed and see only red. I’ve seen second fights just a little bit later be much worse than the first. Not hard to imagine it in a sports scene.
Sucks that it hit Dawson in such a bad way when there was no intended malice. Further evidence of how poor the designation of a flagrant 2 is.