Is modern academia hopelessly toxic and unfair for PhD students?

I have felt that academia is not meant for students anymore. It has become very toxic. I have seen my friends in PhD in STEM suffer so much and ultimately quit or get fired and this has become so common. And most importantly it got nothing to do with how good of a student or researcher they are or how hard they have tried or how much they have accomplished. There is racism and sexism here with a constant pressure of work and publication without taking into account the mental health status of the students. I am a PhD myself in Physics and I am on the verge of a severe mental breakdown. I work as a Teaching Assistant , do research , take classes and courses, face racism and sexism even after working 12 hrs a day, 7 days a week literally from 8 am to 8 pm. I don’t remember when was the last time I smiled or what food I like or what songs I liked. All I do is work or cry in the lab or do self harm cz my self respect and self love is severely compromised. I don’t see anything but darkness. Yesterday one of my two of my friends in their 3rd year from Engineering lab got fired for nothing. My another friend in biology was scolded by her advisor “you’re not good enough” bcz her work got scooped by an alumni postdoc in her lab. My professor behaves very badly with me calling me “worthless, can’t work properly, should leave the group” he does not even pay be from his grants which is why I had to become a teaching assistant. I miss my family, I miss my parents and friends. These profs do not know basic human etiquettes and are creating an environment of toxic work culture with a lot of unpaid or underpaid labourers.
Is modern academia hopelessly toxic and unfair for PhD students?
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