As an impartial party (Saints fan, not a fan of Ray Lewis, not a fan of the Seahawks...but I respect you guys) I think Kam should play. He just signed the darn contract a year ago. He got paid, and now he wants to get paid again. I can respect his talents, and where he stands in the league, but he needs to get back to playing. The man gave his word.
That said, Lewis' opinion isn't worth spit. Lewis is a putz, and he was never put in the same position that Kam has been put in. The Ravens have always taken care of Ray, and he was never just another great player on the teams he played for. Ray was 1 of 2 premier talents on his defense...Kam is fighting to prove he is a top 5 player on his own defense, and he isn't treated like Lewis was.
Lewis knows that this is a business. Teams will cut you, wave you, trade you, force you to take a pay cut, its in his best interest to approach this the way teams do. Sure he is part of a band of brothers, but if he is cut tomorrow, his band of brothers wont be footing his bills. You and I would do the same thing. If you can get more, then get it. It's not selfish when you have so many people you need to take care of.
Also Lewis' perspective on brotherhood is probably different from Chancelor's seeing as how Chancelor has never been involved in a murder case with his brother.