>>130188370He prefers it that way and considers it a part of his identity. No fooling. He's gotten it fixed before, but always gets it reverted cause it "feels right".
Which means that he considers the remnant brain damage he got from literally being dropped on his head an important part of him that shouldn't be fixed. And before you ask, yes, it's retarded, but it's no more retarded than Karma literally getting her leg chopped off to be replaced with the prosthetic that she always hated, or Wiz Kid intentionally staying a cripple in a decked out flight chair. X-men basically see anything related to their personal identities as inviolable, including their actual disabilities and injuries, and will chimp the fuck out on you for suggesting otherwise.