It seems Nvidia's board which had every reason to try to keep him has not reached your conclusion.

Do you simply take them to be fools?

Instead of playing lawyer with you it's quite obviously reasonable to assume the board recognizes his actions open up a Pandora's box of severe legal liability. And quite frankly, I'm not really impressed by your pedestrian analysis of export law. If it was that clear cut he would still be there, and the modus operandi of the Chinese spy wouldn't even make any sense.

For your analysis to have any credibility Nvidia would have to disregard its own self interest. Is that really how you think the world works?