Fair enough. But Arsenal deserved to get reamed. He needed to be checked, right then. Perhaps Nightwing could've handled it a bit better, but I can understand why he did it.
Nightwing was the moron who put Arsenal on the team in the first place despite the fact that he was mentally unstable and had previously tried to kill Lex Luthor. Dick's problems as leader is becoming more and more apparent. The conflicts within the Team are just the result of him ignoring the individual members and playing everyone like chess pieces.
Invasion is essentially Nightwing's Greatest Fuckups.