Why Max Baer was portrayed this way
I know a lot of people have a big gripe with the way Ron Howard portrayed Max Baer. In the movie Max Baer is a heartless killer. In real life he killed a man in the ring but was very remorseful.
Understandably, shedding a historical character in an inaccurate light certainly isn't a good thing to do. Howard had to do it this way. If he shows Baer as an overall nice guy, not out to actually harm Jimmy, then the conflict that Mae feels completely loses it's effectiveness. With Max going out and telling Mae that he was going to essentially kill her husband, it helped to add a new layer to the championship bout. That's just my two cents. Maybe you disagree, but I don't think the ultimate victory, for both Mae and Jimmy, would have been as good.