- promising monogamy to someone who loves you, and then breaking that promise, is bad and provides negative evidence about your character
and
- if you're the leader of a very powerful entity, your character is relevant even to people who don't know you personally.
There's also just the fact that when someone is famous, and it emerges publicly that they've broken some norm, there's not really a fully neutral option available to us. We can condemn their behaviour (reinforcing the norm), defend it (weakening the norm), or ignore it (also somewhat weakening the norm, especially if we make a point of ignoring it and suggest that others are silly for caring).
Obviously it's somewhat complicated when subordinates and Chinese spies are involved, and I'm not condoning infidelity, but IMO infidelity is a reason for a spouse to be justifiably outraged, not the public at large.
It's 'baffling' that someone would think that this is not a social concern.
It transcends cultures and faiths.
We can understand surely that some care less, but the only people who can't understand why this is bad have never been in a relationship.
It is not a north american thing, it is a character thing.
So when one of these representatives of the elite turns out to be not quite so moral, we take special interest in pointing it out until the end of time. If Huang managed a department store you wouldn’t hear much about it.
In terms of facts we have someone who was effectively fired no apparent reason, in 48 hours. Scary.