I would call the first letter semi or pseudo respectful. While she iterates over and over that she is writing the letter because she wants to help (who does she want to help? miley, or her own view points on feminism. highly debatable), she goes on to say things like

"Yes, I’m suggesting you don’t care for yourself." and "Please in future say no when you are asked to prostitute yourself."

While I agree with O'Connor's main points, and she may truly care, if you write a letter to a 20 year old and somehow think that you can conclude that they dont care for themselves and that they are prostituting themselves when you dont even know them, you better be ready for a backlash where they insult you. As far as I am concerned, O'Connor should have never sent the first letter, or sent a way toned down version that was actually meant to be caring and helpful to miley. Not an open letter that was, imo, a chest beating exercise to point out that she acted for a real reason in the past where as miley is not, was insulting, and was meant to push her views of how women should act into the public. It was not a respectful and sincere letter to help miley.