Personally....

I have nothing against slavery. God doesn't either. It's in the bible.

However, I'm against treating slaves badly.
{working them to death, beating them, no time off, or using them sexually or separating them if they have a family...or denying them freedom of religion..}

I mean if you own a slave, you need to treat him/her with some sense of dignity. Got to give them food and shelter and medical care.

It's not a bad system if it is handled correctly.