I have always thought that this type of trolls must have some kind of cognitive distorsion, so that anything different from what they like must be wrong and, by consequence, eliminated.
I have never understood these "OS wars" ("mine is better than yours", "you don't use my OS? So you are a looser"), mostly because it seems to me a kind of "digital extremism", and extremists are, by their nature, obtuse.
Personally, I like - no, the correct term is "I love" - FreeBSD, and nothing else matters (Metallica docet).
I don't care if Linux is faster, if Windows has more games or if Mac OS X is graphically superior - I like FreeBSD and that's all.
Just like I love my girlfriend, I don't care if another girl is more beautiful than mine - and obviously I don't insult the one that is less beautiful than mine.
I usually follow the golden rule "don't feed the troll" and I never reply to this kind of childish posts (though just writing this post means giving them the attention they are looking for), but if I had to reply to them I would simply write:
The entire FreeBSD community warmly thanks <troll_name> for not being a member thereof and, consequently, for having proved (using "Reductio ad Absurdum") that this community is made of higly competent and polite people.