When I was young, and starting into my gaming, I'd normally play on easy for my games (Except Starfleet Armada, I was fucking boss at that and would play against normal bots, and sometimes even the harder ones XD) But Unreal tournament got me out of my shell.
Back before I even started into school, my father couldn't afford to have me babysat and obviously wouldn't leave me at home all the time, so he would take me to work and plop me down on one of the floor's demo Computers, which was running the Original Unreal Tournament at the time XD And I would play that, all the time, whenever he couldn't hand me off to friends and close family to watch. And he would slowly turn up the difficulty on me. I don't remember how far he got it up though (Skilled? Veteran? 3-4 tiers above normal at the MOST) but I do remember sitting down years later to play 2003 and it just... Came naturally. I still boot up 2004 every once and a while and do a 1v1 instakill vs Godlike bots XD
So my decision in a game comes from the type of gameplay. COD usually stalls out at normal for me, because in my "Realistic" Shooters I prefer to take things slow, find solid cover and whittle down the enemy. COD loves to respawn enemies if you don't advance, and kill you in three shots DX. Throw me into ARMA 3 and I'll fight down top skill AI in outnumbered assaults and stand my ground. Throw me into Legendary Halo and I'll hold my own. Crank the difficulty on Vanquish and I'll live.
but you turn up the difficulty in COD and I will rage. So yes, I support easy mode, and its because I am a good example of being real good at a few things (RTS, Fast paced like Halo and Unreal, and slow tactical like ARMA) And being 'competent' at the COD's and the Battlefields, and the "Realism is brown" Generic shooters (no hate, just the general group I tend to lump them in XD)