Product of the times isn’t a great way to put it, but you can certainly make the argument that most people have shades of grey morality.

Science can back you up, too, as I teach social psychology and when you dig in, you find that normative human nature is pretty complex but generally very supportive for in-group and mildly empathetic even with strangers. It’s only when you dehumanize a group do you get the worst behavior, and in all four cases you see that, be it slaves or indigenous people.

When you look at those times, it’s people who recognized their humanity that ended up in the just side of history.