The AP is just relying on the fact that most bloggers don’t have the money to go to court and face them to protect obvious fair use. I’m sure AP will try to get an idea of the financials of any blogger before sending any threatening letters.
As you all know, FR got hammered for the same, with some sites not even allowing the posting of short extracts. FR could have prevailed against such types if it had a sugar daddy willing to put up six years worth of operating expenses for a defense.
And that is the problem in a nutshell- it takes a lot of money to even try to stop this sort of thing. I do hope someone, somewhere does put up the money to take this issue all the way- I do think it could be stopped.
I am not a Supreme Court justice- but I see posting articles on the internet for discussion as no different than folks sharing the morning paper and discussing articles in a coffee shop. I also do not see why any news organization would not want their work distributed. In the real world, not everyone that reads a paper or magazine paid to read it, and certainly not everyone that discusses an article pays for the right. It doesn't make sense to me at all.