I'm not sure if you're aware of the lawsuit over fair use that's going on between FR and the LATimes & Washington Post. Anyway, thats why only excerpts from those two papers can be posted until the suit is settled.
I'm aware of the suit if not all the particulars. I can tell you that I used to work dealing with the murky issue of copyright. There is no clear standard, but there are lots of tradtions and conventions. Generally, the smaller the work, the less you can quote from it. Lyricists and poets have the most established protection...sometimes they can even keep you from using the song title! And we know that important speeches can be copyrighted, as in King's "I Have a Dream" speech, as ubiquitous as the Gettysburg address, provides his heirs with a bonanza in royalties.
Copyright has expanded for the holders in recent times, which I believe is an injustice, considering that patent holders do not enjoy equal privileges. Coca-cola's logo should have gone out of copyright decades ago, but they still retain full rights, as does Disney over Mouse ears.
If the other sources have not sued, it's because they don't see an advantage or don't choose to make the issue.