I don't understand this viewpoint that Joshua gave up or quit against Ruiz in the first fight. He was concussed and the Ref stopped the fight. Would you prefer to see Fighters brain damaged or killed to get your jollies ? This is addressed not just to you Rules but all the other Heavyweight Champions who talk about their disgust at Fighters quitting.
I love Ali but everything you say is true. In later years he mellowed as we all do. He acknowledged his white heritage and visited Ennis, the birthplace of his Great Grandfather. I still believe that along with his feats in the ring, his stance on Vietnam and civil rights outweigh some of the appalling things he did, particularly in respect to Frazier, who as you say, he treated with unjustifiable contempt.