I don't really know why these two obviously fine and classy young ladies are pummeling each other in the midst of a white-water rafting adventure. And frankly, I'm not sure we even care.
The only information we have is from the Youtube title: seemingly intoxicated, probably bimbos, maybe related, whaling each other on the decidedly un-lazy Nantahala River in western North Carolina. Are they fighting over a dude? Shotgun on the ride home? Vehemently disagreeing about 19th Century Italian politics? Unfortunately, we may never know.
It's best to just forget about it, and marvel in the beauty that is these two ladies pullin' hair and clawing face. Because everything else in this world is just too complicated.