Yes there are laws against participating in espionage.

Although a board of directors/shareholders doesn’t necessarily have to care about it being illegal. It just looks really, really bad that the CEO of the company they have invested in and help run is having an affair with what turned out to be an actual spy.

When the company looks bad, the company loses money. Haung’s entire job is to make the company more money. They can try to force him out just on the merits that he has damaged the company stock value.