Firstly, I got my copy of the letter and I hope that I do not exhibit any of the behaviours listed. Therefore I do not believe this letter was intended for me - so no offence taken.
If you don't address such a letter to everyone, it is quite possible that those who haven't been quilty of unacceptable behaviour in the past may think that it will be acceptable in the future.
I'm not management, never have been and never will be but I would rather have a discussion about management trying to address standards rather than one about managements lack of action over such matters.
What I think is really sad is that in a professional company such as ours, this subject needed to be mentioned at all.