I think the moral question is unrelated to the legal matter (which is why he's stepping down), but I'll take the bait on the moral question.

Polygamy is not concubinage is not having extramarital affairs

Making a promise to someone of exclusive sexual intimacy and then breaking that promise is recognized near universally as a moral failing. He knew such an affair would hurt not just shareholders financially but people emotionally.

Maybe the guy isn't totally morally fiberless, but I think most people would agree that such behavior is a (non-trivial) moral failing.

What you’re saying is that (some) men have lacked morals for a long, long time.

Someone please frame this comment for the HN hall of fame

Is your claim that cheating on your wife is a moral thing to do?