I always find these threads really interesting, because of just how polarized opinions become. I loved CoD/2/3/4, tolerated World At War, didn't much care for MW2, and didn't like Blops - so, I'm not a huge fan of the series anymore. That being said...
CoD's success is so controversial in gaming circles, I think, because it challenges our identity as gamers in a way that has never been done before in quite the same way. CoD is a game which is played by people who don't particularly like games - you don't get those kinds of sales figures by appealing to the usual suspects. You need to appeal to the people who play one game, and who see gaming as the console marketplace as an extension of the wider entertainment industry (including film, television etc.)
But, at the same time, it IS a video game, and gaming is notoriously tribal, territorial, and volatile. So, there are 'immigrants' who have colonised gaming through titles like CoD and WoW, and through their massive buying power, have rewritten the rules of how the economic models of gaming will operate, how the social models of gaming will operate, and how gaming is culturally codified.
The problem with THAT is that you have the old guard of gaming 'natives' who really resist all of these changes that are completely out of control, in a sector of their lives which was appealing BECAUSE of their ability to control it. When gaming was for 'gaming hobbyists', we did have mods, independent content, shareware, and a more personal element - stuff like Carmack's .plan file, or the love/hate relationship with Romero. The industry is now radically different, and the tribal element of gaming has roared to the surface around things like Cod - the 'hardcore' vs. 'casual' split and so on. What it really is, is a way of identifying as a member of gaming's original wave of pioneers, versus the new audience of (equally valid) players, who have unwittingly altered the configuration of the gaming landscape.
The solution, I guess, is to amplify your love of the perennial elements of what gaming was. It isn't dead, guys. CoD is a monolith, but you don't HAVE to play it. Give Tripwire your money. Or Taleworlds. Play Quake Live and tell people about it. The anger towards CoD has you identifying the wrong enemy, though. CoD isn't the problem - CoD is the gaming equivalent of Dylan going electric. It is just a part of a new evolutionary wave, and represents the point where the hobby has become a component of wider multimodal culture.
Keep it as a hobby wherever you can, and I'll see some of you on the RO2 servers.