In this case it's not that ridiculous because "black" here isn't just a skin color, but primarily a subculture/subgenre with some distinct musical attributes.

Nobody finds separating French electronic music into its own subgenre ridiculous. Same with Italian Disco.

Such distinct movements are quite usual, so dissatisfaction about Black Swing on streaming services is understandable.

Spotify won't be able to keep those genres separate either.

I think many here are missing the point being made. Of course there are stylistic differences between some groups of artists. The thing is that they probably aren't coded by skin color let alone period location etc, so of course it will bleed. Playing some swing and expecting it to continue to stay within very blurry racial lines is unrealistic, silly, and maybe irresponsible for a recommendation algorithm.

As it's been said, there are better methods of discovery for this purpose. In your example, I'm sure there are Spotify playlists for Italian disco that have been curated.

But these were different music styles.

Also, the subculture exists in the US because of hundreds of years of intentional effort by the majority to destroy any preexisting cultures among black people and prevent any integration with the mainstream.

That's funny, because a lot of 'black' music in that period came from irish musical influences and totally did not come from what you are claiming.

No, he's saying that within the genre of mid-20th century Swing there are distinct musical traditions found in black vs white bands, which he wishes he could partition against. What's ridiculous about that?

Because they all borrowed from each other and the line is blurry if it even exists at all.