within his lifetime, bartolome de las casas went from "slavery is good" to "slavery is only okay for africans" to "slavery is 100% wrong, no matter who it is"
so the "can't judge people in the past by today's standards" argument is utter complete bullshit, because people knew the wrong thing was wrong while it was happening, even after being raised to believe the wrong this is right. if that wasn't the case, we'd still have slavery. segregation. child labor. pretty much everything that got stopped only because people at the time said fuck this shit, and put a stop to it. and yes, there are people who want to go back to those days. fucking conservatives