Because it's not at simple as just not playing those games. The money those games make come at the detriment of every other game and genre, THAT is the crux of the issue plain in simple.
Even if you don't care for, don't buy, and don't play Call of Duty, the games you were once interested in shift to the nickel and dime lowest common denominator cookie cutter million seller cut and paste Call of Duty formula. You can't ignore it, it's a plague infecting the whole industry, not just a handful of games. The business practice that does this is entirely enabled by the drooling masses opening their wallets en masse for their quick fix from these shitty games every month, which means *our* market isn't worth making games for anymore, which is why we hate them so much.
I'll never experience a masterpiece like Final Fantasy VI ever again thanks to being outnumbered by casuals too young to legally own a real gun drooling over "kool new gunz an teh acheevmints" every 3 months. The makers of these games were once proud of making some of the best games in history. Now all that matters is selling a million copies of everything the first day while spending as little as possible (eg: copy/pasting previous assets).
Like RPGs? Too bad, they are all restricted to tunnels and single button mashing battles now. (see: CoD, FF XIII)
Like survival horror? Too bad, they are all on rails shoot em ups and shooting galleries now. (see: CoD, RE5)
Want a platformer or adventure game? I dare you to find one that doesn't have an M4 or dog tags in it somewhere. (see: CoD, etc)