Sega are the owners of CA. So: CA=SEGA, SEGA=CA. To boycott games for windows is to boycott TW.

To be honest I don't really care much about it either way as I don't play online. I do avoid Games for Windows anyway as I've always avoided MS products where possible. Really it's up to the individual, whether they want to buy it or not. I wouldn't like to advise anyone either way. All I can say is that surely it's better to look into this for one's self and not simply comply with someone else's agenda?