This thread reminds me of a funny story: In the '70s, Tommy Gallagher and I used to take our amateur boxing team to compete in smokers all over New York. We had one mouthy, black light heavy with a blown-out fro who dressed like Super Fly comin' into the gym -- girls on each arm--playah! written all over'm. But he not only could talk smack, he could back it up. We took him to box on a card in Spanish Harlem. Even though we told him to cool it, he strutted in the corner before the fight, talkin' trash to the crowd, and it made em crazy. They waved their fists and chanted. He turned to us, perplexed. "They think I'm Jewish. They keep callin' me Marty Cohen."
World war 2 played a big part in the change in boxings demographics. The GI bill, and relationships generated throught the common experience of war with the long standing Americans, helped the middle classification of the poor Italian/Irish/Jewish who up to that point were living packed together in the tough inner cities, they started drifitng out to the suberbs, where they lived nicer lives and lost the inclination to beat other guys up for a living. Meanwhile, blacks who had lived in rural areas in the south moved to cities in the north looking for better jobs and treatment, moved into the same areas and alot turned to boxing, and their numbers in the ring increased massively, and the same thing's happening now with hispanics from various places.