This does not imply it is workers' owned or that it does not have ridiculously high payed managers.

Being a non-profit doesn't make the org structure immune to greed.

I mean, Trump and kids had a non-profit.

Not-for-profit is still a corporation, and the distinction simply means that they need to reinvest profits back into the company. A for-profit company can sit on massive amounts of stockpiled wealth, while a not-for-profit needs to find ways to reinvest that back into the company. To be clear, they can still sit on a lot of money. But all of their money needs to be earmarked for something, instead of just being a rainy day fund.

Well if not because greed or shitty people in management, why oppose unionization?

Open Ai at one point was one too…

Oh dude go look up it's business filings. Foundations are corporations

See: Susan G Coleman