I think most people aren't angry at The Rock because they understood why he did what he did. What person wouldn't take being a Hollywood star over tearing your body up almost every night of the week? Cena would make the same move if he could, but right now it looks like he can't even get a role if the movie is not produced by the WWE so he's making the smart move and being the face of the company and cashing in with his salary and merchandise sales.
I think most fans are angry at Cena because his character is STALE and it's time to make things a little fresh with the guy.
I look at it a little like if Will Smith went back to being the "Fresh Prince" just because his fans want it. He has evolved into something much bigger so it would be sill to go b