I think the issue here is more your own narrow views than the consoles offerings.
The PS3 is the most diverse system when it comes to AAA games. Yes, there are shooters, but why should there not be? It's a gamer favorite for a reason, just like with all forms of media. Why is there lots of war / action movies? war / action novels? Same reason. We love adrenaline. It makes us feel alive, FPS games are good at this.
But that's not nearly all the PS3 has to offer. It has a stellar lineup of titles from all sorts of genres. To name a few;
LittleBigPlanet, most critically acclaimed and innovative platforming game in many many years. 95 Metacritic, receiver of many GOTY awards.
Gran Turismo 5: Prologue. Reviews are mostly down due to this being a demo. Do not misunderstand them. There is a AAA racing game here, its just not much of one. at 29.99 though, thats a great deal.
Fifa Soccer 10 Best soccer game ever created. Nothing else to say really.
Batman: Arkham Asylum: Amazing game. I know there is violence, but then again, there is violence in the wii's best game Twilight Princess. :P
Rock Band & Rockband 2: Nothing needed here.
Ratchet and Clank: Future Series, Incredibly cute AWESOME 3d platformers, arguably the best ever made.
MLB 09: The show, best baseball game ever made.
WipEout: Super awesome arcade racer.
Demon's Souls: While this is a violent game, it is the single best 3rd person adventure/rpg game in many many years. If you like rpgs and haven't played this, you are hurting yourself.
BlazBlue: Calamity Trigger: Anime styled fighter
Flower: Amazing artistic game involving flowers :P
And many many more.
Trine, Motorstorm, PixelJunk, inFAMOUS, Critter Crunch, Shatter, SuperStardust HD and of course
Uncharted 2 and Metal Gear Solid 4. While both of these involve guns, they are third person adventure games, and absolutely phenomenal ones too, the best ever made.
Don't judge a platform by a few games.
The PS3 only has Resistance 1, Killzone 2, Cod 4 and Modern Warfare 2 as "AAA" Shooters. Resistance 2 needs some work IMO.