He's not trying to write anything off and it is a pretty big technicality. nirvana should have omitted that ideological jab to begin with as it was unnecessary and shows his bias for Apple/against Google. Google is more "open source" than Apple in any way that matters, considering Android is currently on devices their competitors (Amazon) are selling. Apple is mostly responsible for WebKit which is commendable and useful but as far as practical considerations go, nobody gives two shits about Darwin.

But yes, engineering should be the focus and people assume the worst with Apple.