They didn’t screen them that well years ago. I was adopted by a paranoid alcoholic, and a neighbor adoptee was sexually abused by her adopted father.
My mother was sneaky with her physical abuse. Nobody ever saw her hit me, nobody saw her pull my hair or dig bobby pins into my scalp. She rationed what I was allowed to eat, so I spent my teens years especially perpetually hungry.
It’s a myth that adoptive families are carefully screened.
I am so sorry you were treated that way.
I empathize with your past. Myself I choose not to repeat or perpetuate. ;) (I was not adopted), but was adopted by my best friends family over forty years ago. I hope you have found life ties that bring out the best in you too!