What I gathered is that Chomsky was genuinely friends with Epstein, even after the sex crimes had been revealed (which is disturbing), but that there's no evidence Chomsky himself did anything criminal or immoral beyond being friends with a monster. The charitable interpretation is that Chomsky is just as easily conned by fun-seeming extroverted people as anyone else. But maybe there's more to it.
While I share the opinion that Chomsky held back the field of linguistics for decades, the belief that technical or scientific excellence has to beget virtues is a fallacy.