The mag'har are refugees. Gnomes went years without a city, and still don't technically have one, yet they were one of the four core Alliance races (trolls, at least, retook their 'capital' and can visit it anytime; gnomes only retook the surface and some of Gnomeregan due to it being a leveling dungeon). And frankly I'm amazed the mag'har got that much considering most of these clans were at war with the Horde until a year or so ago in-lore.