This movie is a joke
They try to make him out to be some honorable, Michael Corleone clone, when in fact he was a ruthless, charmless monster who had no problem showing his true ugly self. (Watch the fabulous "Blowing Up Gotti" videos on The Smoking Gun, and see just how smooth he was; I bet Irv Gotti would change his moniker after hearing what old John had to say about blacks and latinos)
And isn't he the one who ordered the hit on John Favara? There's no evidence that Sammy the Bull had anything to do with it, and in fact, it was Victoria who instigated it because she was a nut too, just like her dingbat daughter. What they suffered at the loss of their son was nothing compared to the terror they wreaked upon Favara's family, especially his own son. Gotti and his whole worthless family deserve the acid bath that Favara's body was supposedly dissolved in. They are all a disgrace.
The film, meanwhile, is pure fiction.