Theoretically true, but not necessarily. First a Devil's Advocate argument, most murderers probably aren't pro-murder, and most theives aren't pro-theft, they justify themselves in some way. Maybe the person the murderer killed slept with the murderer's wife. Maybe the theif only stole a piece of candy and decided a huge store chain wouldn't care. I wouldn't endorse either of those things, but it can be justified. In a society where people are going to have slaves, even if you theoretically oppose slavery, its not hard to justify owning slaves if you're going to treat them better than whoever will own them if you don't. And of course, its not like there were a whole lot of economic opportunities for blacks anyway. Being in a situation of slavery where you were treated well may have been the best available situation. I'm not endorsing it, but its easy to justify. Its not as obvious as it looks.
