Comment by cryptonector

> That's because the north, in particular new england, started industrializing in the late 1700s. While the south, due to a variety reasons, didn't.

Among those reasons was this: that slavery made the capitalists in the South lazy.

> > Slavery absolutely did not benefit the masters

> If it didn't, the civil war wouldn't have happened. The wealthy elite who owned slaves benefited immensely. Just visit a plantation turned historical museum in the south. Most southerners didn't own slaves.

It's a matter of perception: the masters didn't perceive that industrializing would have benefited them much more than slavery ever could, nor did they perceive that slavery held them back. So of course they saw abolition as a threat to their status.