I suspect because of the association of his "hunched back" with evil doing which has generally been made over the years by various propaganda merchants.
As he didn't have a hump, wasn't a hunchback, didn't have a withered arm and all the other images people have come to associate with Richard III perhaps there will also be another re-examination of the historical accuracy of the rest of the things he's been accused of or associated with?
I read a book years ago about him which said he wasn't an evil man with a grotesquely twisted back. I can't see how the discovery of his skeleton will change things. Historians will continue to disagree .