If the list were actually leaked by a stranger and not by Lohan herself, then yes, it is a huge invasion of her privacy. She said that she made the list as part of her rehab, and it should be able to stay between her and her counselors and should not be made public. It is unfortunate that she is always exposed.
I think that list should never have gone public because some matter should be kept private. Although she is a celebrity but that doesn't means all her personal and private life details should be made public. The media should leave these matters and such things must not be discussed in public.
If someone spends a large proportion of their life courting media attention, they cannot feel violated if the media respond to this. There is a vast difference between illegal attainment of private documents and messages and information being handed to the media. If you are willing to write such a list in a public place and then leave it in a general area for the waiting media to pick up, you cannot then complain about it. The better question has to be whether the individuals she named have had their privacy violated.
She is the one who owned up to the "lovers list". She didn't have to say anything about it. Nobody forced her. She could have just said, "no comment" or something like that. I don't think it is an unfair violation of her privacy. It is just gossip but she is the one who confirmed it.