Chilul Hashem

He can call himself anything. The question is what the Torah thinks of him.

Can one call himself frum if he says motzi shem ra or loshon hora?

Depends on which chassidus he identifies with and what the fight was about. If a chassid of Rebbe A walks around with a sign outside Rebbe B’s beis medrash claiming that Rebbe B’s chassidim will never be allowed entry into olam habah, Rebbe B’s chassidim might feel justified in punching the guy with the sign. That doesn’t mean they can no longer claim to be “chassidim” (albeit chassidim sitting in jail awaiting trial on assault charges). Some may recall when the chassidim of a certain Rebbe A had frequent violent “encounters” with the chassidim of Rebbe Z, the brother of Rebbe A, both of whom claimed to be the rightful successor to their father, Rebbe M. I don’t recall either side ever being dismissed as misnagdim.

As my history teacher put it (nicely), “The Rebbes never played well with each other.” If Rebbe A sees Rebbe B “stealing” his Chasidim, you better believe he’s going to react.

THE CHOOSID IS FIGHTING AN ISRAELI BUT THE ISRAELI IS FIGHTING HASHEM!!!!!!!!!!!1
The Brisker Rav’s explanation for why Iyov was punished with physical torment for remaining silent when Pharaoh asked his advice on dealing with the Jews: Iyov the Rav explained could readily have justified his silence with the claim that a defense of the Jews would have fallen on deaf ears. Hence the parallelism of the punishment with its implicit message for Iyov: When one suffers from pain crying out helps not a whit to remove the source of the pain but one cries out nonetheless because “az s’tut vay shreit mehn” (when it hurts one screams). WHEN YIDDEN DO AVEIROS AND YOU DONT SCREAM THATS A CHILLUL HASHEM!!!!!