Slavery's fundamental offense against human rights was not…

““Slavery's fundamental offense against human rights was not that it took liberty away (which can happen in many other situations), but that it excluded a certain category of people even from the possibility of fighting for freedom—a fight possible under tyranny, and even under the desperate conditions of modern terror (but not under any conditions of concentration-camp life). Slavery's crime against humanity did not begin when one people defeated and enslaved its enemies (though of course this was bad enough), but when slavery became an institution in which some men were "born" free and others slave, when it was forgotten that it was man who had deprived his fellow-men of freedom, and when the sanction for the crime was attributed to nature. Yet in the light of recent events it is possible to say that even slaves still belonged to some sort of human community; their labor was needed, used, and exploited, and this kept them within the pale of humanity. To be a slave was after all to have a distinctive character, a place in society—more than the abstract nakedness of beig human and nothing but human. Not the loss of specific rights, then, but the loss of a community willing and able to guarantee any rights whatsoever, has been the calamity which has befallen ever-increasing numbers of people. Man, it turns out, can lose all so-called Rights of Man without losing his essential quality as man, his human dignity. Only the loss of a polity itself expels him from humanity.””

— Hannah Arendt