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The initial part about the negro runner is crap.
The US was indeed racist at the time, and as an olympian and a foreign representative, he got an equal treatment which he was not accustomed to, which together with the event, expectedly excited him.
These left him with good memories of NS Germany and Hitler, since he achieved his peak of his life there, so no surprise he felt the way he did.

Alas, how can it be denied that Hitler was racist against Jews and Roma people, when he caused their persecution?
Is it not fair to claim, that if a man is against a certain race (in this case at least 2) , then he is a racist?
He does not have to be against every race other than his own.

And it is worth mentioning that Hitler was possibly about 1/4 Jew himself and his family hid it, perhaps due to reasons unrelated to race like adultery.

Another thing that is not convincing about that video, is that the SS used troops of foreign races to fight for itself.
Using another race's men to fight and die for you does not disprove racism.
If anything it supports the racism accusation.