My guess is whatever guidelines the bank had for dropping clients were very vague with a lot of leeway for individual actions that no one could be held accountable for.
Well, half the clients of such an enterprise are probably doing something very wrong either legally or morally speaking, for example arms trading, or getting rich from some green energy scam, or perhaps they run an escort agency or a pornographic website, or the source of their money is drug dealing. Is the financial company supposed to step in and become a law enforcement agency?
My take would be, they should only act if law enforcement or government had clear guidelines for them to follow, otherwise we have an expectation that a private company will become a level of government and law enforcement. Do we want that outcome?
The above does not mean that I condone her actions in this one specific case because it isn’t clear to me what she knew about Epstein’s legal status, just reading a newspaper story about allegations about somebody does not rise to the level of being informed of somebody’s legal status, and nor should it, after all, Donald Trump ... say no more.