MW2 wasn't boycotted because of its DRM, it was because the PC version is just a lazily and poorly done Xbox port. They didn't even bother to include dedicated servers and instead resorted to P2P - a technology that has been out of date in the PC gaming world since the early 90s - because that's what the Xbox uses.
I would also like to point out that of the 5 games listed here, MW2 was the only game to be released on multiple platforms. I would be shocked if even 10% of MW2's sales were on the PC.