I don't understand your argument. So corruption is OK because he isn't getting paid as much as he could be? That's like saying embezzlement is OK if you're underpaid.
And quite commonly in white collar crime, this is used as a defense. Volunteer associations, HOAs, where someone decided they were entitled to use the association credit card, or self-deal, etc., as some form of compensation for their efforts being (in their eyes) insufficiently rewarded.
He isn't insufficiently rewarded. He chose not to hold shares. He's already wealthy and holds shares in many tech startups.
All I'm saying is that he doesn't seem like a corrupt person given all the money he gave up on. Maybe that startup gave the best deal to OpenAI and was the right move regardless of his investment in them.