a) because he disqualifies the license as a reason, even though it is actually the reason GNU came to be, without which what most people call "Linux", that is - GNU/Linux would have had little to stand on. So license on its own is an interesting enough reason.
b) because one second of googling would have shown that FreeBSD has numerous technical (his criterion) things that Linux does not yet at a comparable level, including (from the top of my head) ZFS, jails, dtrace.
d) because there are also things which are not license or technical details which matter (project management style, for example)
Comments like the GP can alternatively be phrased: "I'm a bigot about reasons things happen in the real world, and also I'm too lazy to look up if what I believe is actually true. Lazyweb, prove me wrong", and it would get about as many downvotes.