[quote=@Champion]There is no separation of race due to the 'Battle for Existence'[/quote]
To start out the Night Elves wouldn't have contact with the other races due to their isolationist nature, and Arwyn would be their only way of finding out that there even was a 'Battle for Existence'. Once she reports back on the situation, they'd be able tro mobilise their entire population in support of the other races, even if they still didn't entirely trust the smooth ears.