Louis only fought two black opponents of his 26 title opponents.
They were John Henry Lewis, a man who could not see well ( that is being kind ) and would not be licensed to fight today. Mercifully it was over in round one.
And Joe Walcott, who was ahead by fair judges, knocked Louis down twice only to be robbed of the decision. Some rounds can been seen today. The thunderous boos when the decision was announced in MSG can be heard which was home to many if Joe Louis title fight can be heard. Louis walked away with the body language of the loser. 2/3 of ringside boxing people scoring the fight felt Wlaccot won it. So Walcott won it the first fight and was well in the lead of the rematch before he got cute and was caught.
Some fell that Chalres should count as a title defense as it was the national boxing association title ( 1921-1962 ). Chalres really beat the doors off of Louis, busting him up with something fierce in the 15 round decision, though Louis was 36. Speculation on my part is Charles would have been trouble for a prime Joe Louis.
But what about the balck men who Louis never fought or I say ducked in some cases? The below is not my work but I am borrowing it for the purpose of this thread.
I looked up how the black fighters mentioned did against non-black heavyweights who got shot against Louis.
Turkey Thompson - Beat Godoy, was 2-0 vs Gus Dorazio, 0-2 vs Pastor, had a draw with both Simon and Tony Musto.
Jimmy Bivins - Beat Tammy Mauriello, lost to Musto, 1-1 vs Pastor.
Lem franklin lost to Pastor and Dorazio, beat Simon and Musto.
Roscoe Toles - lost to Simon and Pastor. Beat Dorazio, and Harry Thomas. 4-1-3 vs Godoy.
Blunt - lost to Galento and Red Burman. Beat Musto. 1-1 vs Simon. 1-2-1 vs Nathan Mann
Leroy Haynes - lost to Galento, draw with Godoy.
Grand total: The black fighters went 16-15-7 against the non-black fighters that got title shots. That's pretty close.
You can make a reasonable case why any particular black heavyweight never got a title shot at this time. However, it's pretty obvious that black heavyweights were being frozen out by Louis
Other who Louis did not fight were Elmer Ray was TOP CONTENDER AND Tiger Fox who made HALL OF FAME.