I haven't seen any evidence that Shatterspear dislike birds, and have seen several people RPing them as revering the eagles...
I found this quest as the ONLY evidence that the
Darkspear dislike bird spirits.
http://www.wowhead.com/quest=9846
Hmm... They seem to be divided between images of a serpent spirit and a bird spirit. No self-respecting Darkspear troll engages in bird worship. Their spirits are weak, capricious, and best left to the Amani.
This sounds more like
Darkspear thing to me, similar to some tribes worship certain Loa and others do not. I mean, until recently, Gonk did not even exist in lore, but apparently he can beat up all the other Animal Loa so they would work together?
As for the Sandfury, mine is more technically a
former one. I always thought it was a bit silly to claim you're an enemy of the Horde (or Alliance) and then walk around in their cities. Khi was born a Sandfury, but is technically no longer a member of the tribe and has not been for a while (possibly pre-Shattering, I'm still working on the details). I have seen some in-character 'racist', which is just fine and expected. Khi herself is a more than a bit untrusting and standoffish to most, including other trolls. I have yet to have anyone outright complain OOC about her choice of tribe, though I admit, I am going a bit 'outside the box' for the fun of it, but I adore desert cultures.