Most of the world was introduced to Sinatra and “Ol’ Man River” in the MGM biopic which followed the death of Jerome Kern of a sudden heart attack on the streets of Manhattan in November, 1945.
The film ended with a group of MGM stars performing Kern songs. Skinny white Sinatra was last. Horrid, I thought.
Fast forward to a civil rights benefit at Carnegie Hall in the early 60s. Sinatra on stage singing the anthem, but a mature Sinatra performing it slower and with deep feeling. Legend has it that Martin Luther King, sitting up front, wiped away a few tears. Daughter Nancy, who was there, attested to it on her weekly SiriusXM show. So Sinatra is probably safe from criticism, although I still much prefer Warfield or Robeson.
Incidentally, that Sinatra performance was featured on his very good 1967 television special that included he lots of Ella and not enough Antonio Carlos Jobim. It is part of Prime video and can be watched for free with ads.