The title is really misleading, he's saying it doesn't make business sense to make ports of games to Linux, and it doesn't... It's penetration in the market is very low.
This is not even that surprising. 12 yrs is nothing compared to the inhuman amount of time it would take to port it, and considering how much work into it in the first place(?).
I'm a linux user at home and at work (for everything except starcraft), but I don't feel the need to pretend otherwise.
But read that stat again. 20 times. For every linux user there are 20 windows xp users, and 35 windows 7 users.
[1] http://en.wikipedia.org/wiki/Usage_share_of_operating_system...