I was reading that Hitler stormed out of an event over a black man in the Olympics. Meanwhile last night, Kenya almost won gold in long distance running. Was the addition of African competitors a recent thing? We're they not allowed or able to afford to enter?
In regard to Jesse Owens during the 1936 Olympics, Hitler did not storm out. What happened however, was that on the first day of competition, Hitler shook hands with only the German victors and then left the stadium. Olympic committee officials insisted Hitler greet every medalist or none at all. Hitler opted for the latter and skipped all further medal presentations.
Historians have noted that Hitler may have left the games at this time due to looming rain clouds that might have postponed the games. This happened well before Owens was to compete, but has largely come to be believed to be the "snub".
While Hitler did react in private, he had no public response to Owens' succes as Albert Speer wrote that Hitler "was highly annoyed by the series of triumphs by the marvelous colored American runner, Jesse Owens. People whose antecedents came from the jungle were primitive, Hitler said with a shrug; their physiques were stronger than those of civilized whites and hence should be excluded from future games."
I don't know about black competitors from Europe or North America before 1936, but I do have some basic info to add about when African countries started competing. Egypt and South Africa have been involved since the very early days of the Olympics, but it wasn't until 1952, with Ghana and Nigeria, that predominately black countries competed. Many more would follow in the next 4-8 years.
Hopefully this is ok to post, I just mean it as additional info that's related to the question.
Keep in mind many African countries didn't even exist until the 60s. Only Ethiopia before 1936 and after WW2 as well as South Africa and Liberia existed. Though I haven't a clue as to who participated.