I tend to agree with M.C. on this.
I think it's silly to say that CoD is a bad game, because of the 'random game mechanics'. If CoD didn't have killstreaks, perks etc. I doubt I'd even be playing that game as much as I did, because for me, that is what made the game fun. Sure, when I played it, I played it to win, but more importantly, I played it to have fun and pass some time. If I did it solely for the purpose of competition, I would've participated gamebattles (where there aren't any perks, killstreaks and such btw) or played CS.
I do agree though that the skill gap between good and bad players in a game like CS is bigger than a game like CoD, which is also one of the reasons I don't play CS but play CoD. Obviously, no one wants to get demolished at a game, and it takes more time to get good in CS than CoD, and as a casual gamer, who only plays video games just a couple of hours a week, I prefer CoD. I just wouldn't have time for a game like CS. I did play it A LOT some years back, and the reason why I played it is because I had more free time.