All the mountaineers are.
Maybe it's because they have no slaves themselves and hate the more prosperous and more civilized lowlanders who do have them.

Harry, my boy, as you grow older you'll find that reason and logic seldom control men's lives." "Skelly was excited over the news from South Carolina," said Harry, continuing the story, which he, too, had read, as an Indian reads a trail, "and he began to drink.

He met Travers and cursed the slave-holders.

Travers replied with a sneer, which the mountaineer could not understand, except that it hurt.

Skelly snatched out his pistol and fired wildly.