Many of those who "make it" and get those vaunted prestigious TT jobs are also desperately depressed in many cases (at least up through getting tenure, but even afterward the whole experience seems scarring). This seems to select for incredibly dedicated and usually quite intelligent, but also very obsessive and emotionally fragile people to finally make it through into permanent employment in academia. They then often have similar expectations for their grad students to do the same as they did, even if they claim on social media to be "caring" and such.

There are a couple ways of looking at this, yours is one take.

We can look at it another way. The kind of people with the intelligence and persistence to successfully complete a Ph.D. are disproportionately neurodivergent, IME. You’ll find a lot of people on the spectrum at the upper ranks of academia. Such people lack in dopamine production, and may end up taking medication to deal with that as they are diagnosed during the course of their graduate education, which typically provides access to healthcare and therapy.

I have a physics PhD. I had a good experience. My advisor really went to bat for me, and was supportive when it became apparent that I wasn't destined for a rockstar career, even though he was a rockstar himself in his subfield.

There is something about the "failure is not an option" experience that molds people for certain kinds of work. I still work on the same kinds of projects, albeit not in the same field. But I sincerely wish it didn't produce the human cost that it does. The risk is too great.

Noting a sister comment in the same thread, when I was in grad school, students had no access to healthcare or therapy.