Nah Hawk's story progression makes sense. There was none of his friends left at Cobra Kai. He was pretty much the last man standing of his friend group.
Miguel? Went to Eagle Fang. Aisha? moved away. Dimitri? Hawk tried to be his friend for a long time. It wasn't until Dimitri constantly attacked things he loved (Cobra Kai) and belittled him publicly that he turned on him. Even in season 2 they were teasing that they could still be friends. But he ruined it there. Mitch? Got kicked out of Cobra Kai. Bert? Got Kicked out of Cobra Kai.
Then look at characters that Hawk does not like. Kyler is #1 with a bullet. He hates the dude and seeing him beat his friend Miguel was enough for him to finally jump ship.
It's not that it didn't make sense, it's that it was poorly executed.