As you can verify, I wasn't the only one who received the same comment. I was wondering if it is wise to try to enforce a current policy on very old contributions. I feel it is too much to ask for a huge amount of users. Maybe this is our online version of retroactivity in law.
The book policy is only retroactive in a fashion. Answers which do not follow the current policy are deleted and replaced with a community wiki list having the same contents.
There is no need to comment on every answer and ask for it to be fixed -- if you want you can do that, of course, and if the answer is deleted before you get a chance to fix it you can post a new one.
I have yet to go through all the old questions and new-ify them, I have only done this for a couple of posts so far. I'll get to it this week.
@Emilio to be clear, there is no need to comment but the rest of what you did on the post seems about right, carry on :)