Originally Posted by def28
Why not? He's already an X-Men, you don't need to explain something like that. All mutants are being hunted. Who would you help and want go to? Probably the X-Men. All X Men are disbanded in The Wolverine anyways and thats probably the same case at the end of the film. So technically everyone will have been gone when we walk in the theatre.
Nope. Just because he worked with the X-Men in X2, it doesn't instantly make him a X-Men. He didn't appear in X3 and its lazy just to bring him back in DOFP as a member of the X-Men right away.