I read the article and I completely agree with you here. I said I would've been pissed too if I was still online gaming on a PC. The author was definitely not empathetic towards the PC crowd by referring to them as "nerds across the world" and it was shitty to announce it three weeks before release.
I know IW stands to lose money from the sale of PC versions, but how much we really don't know. This game is going to be one of the best selling games in history, regardless of platform. Is the entire PC community really not going to buy this game now? Really? You know that if the game itself is good enough, a lot them will cave no matter what they are posting now. And if those same people do cave, what's going to stop them from purchasing DLC when it comes available if they can no longer modify it themselves or buying MW3 when 2 becomes stale.
I don't like the way it was handled any more than you, but I can see why the developers are doing it on a business side for themselves.