Following that, we can take a look at the harm done by Epstein and do some comparisons.
As it's a moral question, there's not going to be any unambiguous right or wrong answer and we're all going to have different perspectives. One might even argue that you have a moral imperative to take his money for practically any reason so long as you are not directly assisting his other actions, since it means you are taking a chip, regardless of how small, out of the resources he had to carry on with said other actions.
As another example on this topic in Columbia the big drug dealers would frequently use their ill gotten wealth to do positive things such as fund schools for local towns. And these guys were involved in far worse behavior - murdering large numbers of people, often in brutal fashion to send a message. And that was similarly no secret. Should the townspeople have rejected their offer?
But you replied to my point about abusers exploiting the well-meaning and naive. I don't see what bringing up an obvious fact about moral complexity does here, especially since you refuse to engage usefully with your own point. Except of course to confuse the issue.
In practice, I don't think I've seen any attempts by Epstein associates to really grapple with the moral balance, to weigh the ends against the means. What I mostly see is them taking the money and either supporting him or dodging the hard questions. There isn't anybody willing to say, "Yeah, I suspected he was a manipulative, sex-trafficking pedophile, but I was cool with it because here's what the world got out of it."
There are plenty of good places to discuss moral nuances. But maybe try it in a place where it doesn't derail from holding people accountable for their behavior.
Online 'accountability' often heads directly into the domain of mob mentality. I think if more people stopped to ask 'hey is our outrage even really justified?' that the world be a much nicer place for everybody.
And neither do you, or you wouldn't be here arguing for some very specific moral choices of your own. You claim you're not taking any specific position, but you of course are. Your repeated intervention in the discussion demonstrates that. And your unwillingness to spell out the implications of that position is telling.
Of course he gained in the exchange. He was an astute buyer of prestige, of legitimacy. Look at the scientists who went to bat for him after he had already been indicted, even convicted.
According to friends, Epstein showed up at a TED conference circa 1999 with 6 plus-ones, all listed as "Mrs Jeffery Epstein". (The tickets were something like $5k in 2019 dollars.) They don't recall them as being under-age, but it definitely seemed sleazy. Their recollection is that Epstein used them to meet people; the women would go chat somebody up and bring them back to Epstein.
Abusers are well known for grooming victims, but they also groom allies. So it's not surprising that among this list we find people who are either hopelessly naive or of dubious character themselves. In retrospect it doesn't seem like a coincidence that around the same time Bill Clinton and Kevin Spacey were zooming around on Epstein's plane.
Let that be a lesson to all of us. If we suddenly experience an overwhelming amount of positive attention, it's worth asking ourselves whether it's the love-bombing [1] common to narcissistic manipulators.
[1] https://en.wikipedia.org/wiki/Love_bombing