Close/open-mindedness isn't about being morally wrong/right. It's about holding a vile idea in your head long enough to see its various facets. To study it and understand it.

Openmindedness here means being able to understand that slavery is wrong at the same time you study what it reveals about the human condition. To be clear, no one in this thread has argued that slavery was good. If you think that, then maybe it's a sign that you're not separating subtle ideas well enough.

All cultures have differing views on rights. So any culture will have elements that I see people whose rights are being violated. I guess I will have to avoid reading anything about them, unless the author takes an appropriately moralistic and judgmental tone, of course. I have to assume that I am right and everybody else is wrong. It's the only way to be open minded.