The ambiguity of M. Kamal's ethnicity is due to annihilation of archives related to his ancestry. Most likely he was Donmeh [a fake reverted Jew]. As for the backbiting goes, it is allowed to speak up against Fasiq [publicly corrupt] in exposing his Fisq [a public corruption]. So if anyone indulges himself in a sin such as Israf [extravagant spending] which is haram, publicly he doesn't deserve the honor of not being spoken against.