-You don't. Its a guilt by association angle: even when he knew Epstein was criminally culpable, just like the dodgy prince he still kept meeting him. It's in the article:
"When asked about his relationship with Epstein, Noam Chomsky said: "First response is that it is none of your business. Or anyone’s. Second is that I knew him and we met occasionally."
"After Epstein donated $850,000 to MIT between 2002 and 2017, and $9.1 million to Harvard between 1998 and 2008, Chomsky said in a 2020 interview that people 'worse than Epstein' had donated to MIT. He didn't disclose their friendship at the time."
"Chomsky said that at the time of their meetings, "what was known about Jeffrey Epstein was that he had been convicted of a crime and had served his sentence. According to U.S. laws and norms, that yields a clean slate."
...So who knows. Maybe he was intrigued by the gangsters who run the show and how their minions operate? Maybe it was just the MIT money? Epstein knew a huge number of important people: that was his "job" apparently: many more than are willing to admit it.