The REAL Bumpy

Although this movie was entertaining, it was, indeed, factually inaccurate in many, many respects, not the least of which is in trying to make Bumpy Johnson a "humane" character.
In fact, Bumpy was from South Carolina, moving to NY and never being anything but a criminal. He was a true thug (with a capital 'T'), resorting to serious violence -- albeit fearlessly -- at the least (even presumed or imagined) provocation. If I recall correctly, he once even stormed into a police station (or was it the hospital), shooting (killing?) a man there, due to the fact that the man (victim) had survived Bumpy's earlier attempt to kill the man.
He was truly violence personified.
That being said, he did use some of the power he acquired (due to people fearing him) to help out the less powerful in the Harlem community, e.g., forcing the Cotton Club to hire some, including certain black musicians.
He also used it to help Ms. St. Claire (the character of "The Queen" who, prior to the mob trying to take over, alone held sway over the numbers game in Harlem).
This did, in fact, put Bumpy in direct confrontation with "Dutch" Schultz ... and that violent part of the movie is true.
I think it would have made an interesting movie to have simply focused on his terribly violent and unrepentant character, for his REAL story is actually pretty compelling.
It also would've added enough elements that ridiculous fictions (e.g., Thomas E. Dewey being on the take from "Lucky" Luciano, "Dutch" Schultz being gunned down by his own henchman, etc.) wouldn't have had to be included.