I think the swimming comment needed a big sarcasm alert based on old stereotypes, which is the way I read it.
Stereotype?
Nope. Reality:
Just under 70% of African-American children surveyed said they had no or low ability to swim. Low ability merely meant they were able to splash around in the shallow end. A further 12% said they could swim but had “taught themselves”.
https://www.bbc.com/news/world-us-canada-11172054