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That's a profoundly uncharitable view of Ali as a person, and its devoid of the context of his time and his relationship with both his country and the Nation of Islam. Firstly, I'm firmly of the opinion that the racialist attitude of blacks in the 60s were excusable given the diabolical oppression they suffered. Ali had to experience his mom getting kicked out of department stores looking for a bathroom for him to use, couldn't eat in downtown restaurants, and all kinds of daily humiliations. America was a society that tried to program blacks to believe they were inferior, and in response some blacks attempted to inoculate themselves rom this racism by taking the opposite position (blacks were superior). Excoriating Ali for being a racist ignores that he was a product of a racist society. It also overlooks the fact that although he said racist things in the abstract, he always treated everyone (white, black, Hispanic) with care, especially children. I'm not just making that up, look up his interactions with white kids, those are not the actions of a racist.
This brings me to my second point. Ali was beholden to the Nation of Islam and relied on them for many things, security being one, and a sense of community being another. Remember Ali was the most hated man in America at one point and was in no position to alienate the NOI. What this means is he parroted a lot of their positions and stances, one of them being segregation. It was under that circumstance that he met with the KKK and spewed all that nonsense. People that know him swear that he never honestly believed that garbage but felt a sense of duty to Elijah Muhammad and the NOI.
Finally, you're being very selective in how you form your opinion of Ali. Of course he's said and done some bad things. He was a public figure for over 50 years and was involved in one of the most polarizing periods in US history (the 60s). But the overwhelming majority of evidence suggest that he was a profoundly decent human being. Whether its reporters who have witnessed his interactions, or fans, or childhood acquaintances the consensus is that he was a sensitive, caring, and generous man. Even Mark Kram admitted this. That said, he was a human being not an angel. His treatment of Joe Frazier is probably the biggest stain on his record, but why should that alone define him? Its an unfair bar to set if you dig up every negative thing he's done without the context of him as a person.