Actually Deep Gnomes, given that most worship Beryl, are fairly well accepted if they chose to surface. The trust and acceptance issue tends to more on their side than the other races. They are rare on the surface for that reason, not that they are drummed out.
That said the local history of some village or hamlet on the map is likely of world changing importance.
Wait, are you saying that Deep Gnomes are hated like Dark Elves and Deep Dwarves?! Since when?!