I don't see the issue as being fundamentally about whether or not it is proprietary per se, but Apple's choice of technology makes it clear that Apple's actions

I don't see the issue as being fundamentally about whether or not it is proprietary per se, but Apple's choice of technology makes it clear that Apple's actions are self interested, and not philanthropic. Philanthropic means "seeking to promote the welfare of others, especially by donating money to good causes; generous and benevolent". It does not mean "selfish action which happens to also benefit others" There are several ways apple could have been less obviously self interested, not purely by choosing FLOSS.