DeForrest thought Johnson comparably great (to Dempsey), but favored Dempsey both on individual qualities of grim determinations and also a (presumed) racial tendency of whites to psychologically dominate blacks. DeForrest trained Firpo , who got handled with ease by Johnson (nearing mid 40's) in a few rounds of sparring.
This article, cited on the web as 1939, apparently recycles an earlier interview with DeForrest, who died in 1932. ( https://www.njboxinghof.org/jimmy-deforest/ ) Given the racial views expressed, it would have been interesting to have seen whether DeForrest's outlook endured during the Louis reign, or subsequent decades.