But how do you know Minsky didn't "ask[] some very hard questions"?
At the time of the alleged sex, 2001-2002, Epstein's cover as an investment billionaire who threw money around to win the attention/affection of young-but-legal women was still secure. He'd been a recent repeat visitor to the Clinton White House, and President Bill Clinton's multiple trips in Epstein's plane were contemporaneous or followed soon after.
The thinking at the time would have been: "If an ex-President (and husband of sitting Senator Hillary Clinton) can hobnob in public with this guy Epstein, he can't be into anything too shady, can he?"
Legitimate question, I haven't been following this closely enough to know. If it was reasonable to assume she was an adult I don't see an issue with it, but I don't have a moral objection to prostitution
(Of course, there's also reasonable debate as to whether or not Minsky actually had sex with her. One person who was present at the gathering claims Minsky didn't.)