Ali coming up was Cassius Clay. He became Ali at the time of the first Liston fight. Ali was associated with a group that can be described as a racist cult. When you look at pictures of Ali from that era you can see Louis Farrakhan beside him. Perhaps you like Louis Farrakhan but most can see him for the racist demagogue that he is. Ali is no different, except while the press loves Ali they revile Farrakhan.
Ali, claimed to be a clergy person in his racist cult, avoided the draft. Because the media is massively liberal, Ali at this point became the darling of many in the media. He was one of the greatest heavyweight champions, without any doubt. I was first introduced to boxing in the buildup to Ali-Frazier I. I liked, and still do, the Henry Armstrong constant attacking style that Frazier employed. At that time athletes presented themselves in a humble, non-boastful manner. Ali and Joe Namath were the two examples of athletes who were not humble. Namath simply guaranteed a win. Ali ran his mouth non-stop. In that era, it was reprehensible.
Today it is common and even typical for athletes to be like conor/ Ali. Conor doesn't grate on us as much because the act has been played thousands of times now. Conor's white; so use a name of a black athlete. It's the difference between Jim Brown not spiking a football and high school kids hot dogging. Watch interviews of Joe Louis, Jersey Joe Walcott, Rocky Marciano and they form the precedent for how a champion should act.
Finally, Ali was living in a contentious racial era and would have been hated by many for simply standing up for himself. Add on top of that, he adopted a minority religion. He was going to have haters but he didn't need to lie about the story about throwing his gold medal in the river (it has been reasonably established that he lied.)