Coffee, you’re going out on a limb to say that paul really did that; it’s not as if it’s in chazal… it’s a theory from a prominent frum historian and talmid chacham, but i wouldn’t take it as a given.
But leshitascha, i think chabad is not irredeemable, pardon the pun. They still keep halacha and believe in torah she baal peh, which makes them able to be saved…could be in a few decades people will wake up, and the tzfas-nik chabadskers will, indeed, be a different religion, like shabsai tzvi followers post-conversion to islam.