I am morally opposed to private prisons and have a very low opinion of juvenile justice in general, but unlike say marriage equality, where I assume most reasonable people are bound to share my beliefs, I do not assume that everyone believes private prisons are evil.
Consider that juvenile abuse is endemic in the entire juvenile justice system, and that (a) a reasonable person might believe that private prison systems are actually more accountable for abuse, since the market can respond to their mismanagement (and because it is far easier to sue a private enterprise than a government agency), and (b) the statistics could conceivably bear this out. I don't know. My problem with private prisons has to do with incentive alignment. But maybe Richard Henriques disagrees with me?
Remember: the Gates Foundation endowment is basically a large private hedge fund that happens to have a charity as its beneficiary rather than a bunch of rich old dudes. The expectation that it be managed differently than any other fund clearly exists, but I'm not sure why that explanation would be valid. There are probably a bunch of universities that hold that private prison stock too.
But here's where we get back to how silly the article is, especially here on this thread: that private prison company is a tiny fraction of the endowment's equity portfolio. It isn't even listed above the fold in the article! The article concerns itself with the suggestion that any support of western consumerist capitalism is hypocrisy on the part of the Gates Foundation. What makes me think that? Because the first page of the article concerns itself with the Foundation's investment in Coke, McD's, BK, Taco Bell, and Pepsi. The article has an unmistakeable and ridiculous thesis.