and people play the COD games you're referring too through steam? Unless there is some unheard to me underground COD4 playing hardcore network of neckbeards I haven't heard of?
Those stats are for the activity in the steam games. This doesn't include WoW and LoL but I never said those where lower on the list, I said that Older COD games are still not played in the "Most 5 games on PC" at least at the current time. Sure on release maybe, but now, WoW, LoL, DOTA2, then probably Starcraft after that point. If you look on that list in the link i provided you should see that COD4 and COD2 are way down that list by clicking view 100 most played games or whatever it is and if you look at the peak you see that none of them come close.