Well.
It's not stolen if Sony never owned it in the first place. All of these titles are third party games. Third party games can be on any console. Last gen it just happened that the PS2 had a big enough userbase that would buy the games and make up development costs. This gen, not so much. So Capcom, Namco, and Konami are doing the smart thing and getting their games on multiple consoles to maximize how many people are able to buy it. The more people can buy their games = more money for them.
Sony does have some good first/second party stuff though. I still think Heavenly Sword looks good. And unless things get really bad for Sony, I doubt that Naughty Dog or Insomniac will jump ship anytime soon. So any Ratchet & Clank and Jak and sequels to Resistance will still be on the PS3 only. And you know inevitably there will be God of War 3.