I don't think the point of what was written is to say that physical fitness is unimportant and that philosophers thought it was just for jocks. It's rather that we're currently facing an emerging culture of striving for perfection that wanders somewhere between insanity and
oppressiveness, that it's often used as a marketing ploy, and that it's perhaps (ironically) not very healthy.
I don't know what it's like where you live, but it's cultish where I am. People aren't just trying to improve themselves, they live for it. It's stifling. I figure it's not quite as bad away from Silicon Valley.
You can't just be a person who likes to try different foods, you have to try all the different foods, accumulate Michelin stars (of food you consume, not produce, of course), learn how to use a sous vide, etc.
You don't just go to the gym, you go to the $250 gym. In your $500 gym outfit. You go every day. And every night. For four hours. You go on a serious food cleanse, etc. etc. Your body is chiseled.
You don't just go to therapy. You go to CBT. You do scream therapy. You do MDMA and LSD therapy (I don't know if that's a thing, I made it up). Go meditating. Go to Burning Man. You're one with the universe. You get the idea.
I'm not going to rewrite the article, but the behavior is real. It's "work hard, play hard", no, work hard, everything hard, to the extreme and logical conclusion. Physical fitness is just one small part of the culture.