Changing one's opinions and outlook on life is not a bad thing, despite calls of 'flip flop' that the media throws out when new facts are presented and people change their outlooks. When confronted with new data, the ability to use your common sense, logic and reason to change conclusions is a true sign of adulthood, IMO.
McCain was against MLK day in Arizona because his constituency is elderly racists. As we used to say back home, Arizona is a drier, whiter, more racist Florida. His stance was a full 15 years, nearly a generation, after MLK was killed and nonviolent protest and engagement won the initial battles for civil rights. If he said these things in 1973, I might give him a pass as it was still too early to see if the civil rights movements were going to devolve into open warfare or not. Robert Byrd was a full on upper level leader in the KKK that then turned into one of the most progressive people in the Senate. Byrd spent the greater part of four decades working to seek, if not forgiveness, then at least reconciliation for his past. I don't see that in McCain.
My problem is not that he changed. My problem is that the media is in love with the guy and a lot of his history is going to be washed into the memory hole by all his media buddies and he is going to be painted as some noble moderate Republican when he was really not. McCain has never really had a spine from what I was able to see and only stood up when he thought it could get him closer to the White House. And I say this as a guy who wanted McCain 2000 to be the nominee.