Horror stories aside, the bulk of southern slaves weren't violently mistreated. They had better working conditions, often times more food and the slave owners had more of need to keep them healthy. In the north industrialists could simply move on, dump a worker and get another; just read what some of these men and women wrote about their workers, many of these men had less of a sense of duty towards their workers than many slave owners had towards their slaves.

To say there is no comparison is to miss the point. Granted slaves were often beaten and whipped, not to mention their complete lack of freedom. Look at living conditions; access to food, housing, medical attention, etc and you'll begin to see that there really wasn't much of difference in those areas of life. Northern factory workers had to do for themselves; which usually meant doing without and living well below the poverty line despite their consistence work and income. Slaves were a massive investment, they cost a lot of money to buy, and simply a pure monetary interest in their slaves kept many slave owners from mistreating them. Just look at how Jefferson Davis' family treated the slaves they had; now compare that to the extremes of violence in the Caribbean and those presented by Abolitionist movements.

Slavery was dead wrong, but to suggest that all slave owners tortured their slaves is also incorrect. So is attempting to say you can't compare the two labor practices. And no, northern immigrant labor