If you witnessed a supervisor exploiting women and numerous complaints resulted in nothing, would you confront him?

Yes/no ... depends on a multitude of factors. As there are many different courses of action that can be taken, confrontation may not be the best route.

• What is the exploitation that was witnessed?
• Who were the complaints made to?
• Were the complaints ever investigated or were they dismissed? If so, why?
• etc.

Not enough information to make a properly informed opinion/decision

I don't have enough background details to firmly declare what I'd do in this situation, although I'd certainly want to act in a way that solves the problem. Would it be my supervisor, a subordinate supervisor within my scope of responsibility, or a supervisor in another organization? My relationship to the person plays a role in how I'd address it. Also, were the complaints made to him directly, or to someone else who took no visible action (chain of command, IG, EO, etc.)? That would also play a role in my decision.