[TristanKromer]

That's not an inherent property of capitalism.

Capitalism rewarded the slave trade for generations.

The invisible hand is really human preferences. That's what will determine whether a company is punished for sexism or rewarded.

Humans stopped Apartheid. Not the abstract concept of capitalism.

[d0lph]

To the contrary, non-slaves produce more value than slaves, therefore slavery is not only unethical, but also un-capitalistic.

Capitalism explains many things, certainly people stopped Apartheid, but it can very well be both, slavery and segregation are unproductive, and therefore anti-capitalistic.

[amirmc]

> ... non-slaves produce more value than slaves,

Probably not to the slave owners, or anyone involved in the slave trade. They had little incentive to change.

Claiming that capitalism somehow spurs these things is the wrong way around. It can certainly benefit, but it's not the driver.

[d0lph]

To the slave owner yes, but their entire productivity is lower, it's better to have a businessmen rather than someone who can just pick cotton and do basic chores.

I think capitalism has a hand to play, to ignore it is naive. I think there was not one driver that ended slavery, but many things working together.

[TristanKromer]

I'm not 100% sure but, I think you might be referring to utilitarianism, not capitalism.

[d0lph]

Certainly it is a utilitarian argument, but in the capitalistic sense a business (plantation) that uses slaves is less efficient in terms of net productivity of the slave than if the slaves were free and instead workers competing to improve the business.

Note: I'm not saying there is no moral reason slavery is wrong, just that in addition it is contrary to the nature of capitalism.