I love Reach and Moas as well, but that AI is completely incorrect. If anything they should wander around in packs, and after attacking one they should all flee at high speed (maybe 2x player run speed). A moa should under no circumstances attack a person. Otherwise I support this idea.
This is not supposed to be 100% accurate with whatever behavior our own prehistoric moa bird may have been.
Geez, I'm pretty sure if he knew it would stir up all this "controversy" he wouldn't have used the name.
(It didn't have wings! Why can you ride it! Moas couldn't be ridden! They should travel in packs! There were no sea moas! Why does it have teeth?! They should be aggressive...)