Oh, cut her a little slack, Frank! She was a person who thought out loud on paper. She toyed with an idea, went round and round it, turning it over and upside down, trying out different stances along the way. It's understandable that she wouldn't "get" pith.
She tends to bring out the worst in me, Cynthia. One of the meanest reviews I ever wrote was of I, Etctera, her short-story collection.
You'd like Terry Castle's famous piece on her, then – though it's not a take-down of her. More a take-down of us.