An earlier article mentioned her recently-published diaries, showing she was cogent enough to write down her thoughts about tea parties and other events in her life. The article very pointedly said she was "mildly" retarded.
Yes, maybe she was mildly retarded. But she was born in 1921. Things were different then. Lobotomies were state-of-the-art treatment. We know better now, but attacking her family for trying to give her the best treatment is wrong.
I hate the Kennedy's for their political work. But I never thought they hated their own children.