I think stuff like this is why there are articles saying ‘exercise culture is fascist’

Probably plays a part of it, but the main reason why is because fascism has always been obsessed with aesthetics, individualism, and the concept of übermenschen. Much of our modern health & wellness industry is focused more on aesthetics than actual health outcomes. A lot of it can be traced directly back to the eugenics movement in the 1920s.