[JaumeGreen]

200 years ago slavery was more extended and accepted than today. 50 years ago paedophilia, rape, and other kinds of sex related abuses where more accepted than today. 30 years ago erotic content was more accepted in Europe than today, and violence was less accepted than today.

Morality changes, what is right and wrong changes.

This is accepting reality.

After all they could fix a set of moral standards and just change the set when they wanted. Nothing could stop them. This text is more honest than the alternative.

[pc86]

"Slavery was right 200 years ago and is only wrong today because we've decided it's wrong" is a pretty bold stance to take.

[JaumeGreen]

Not "slavery was right 200 years ago" but "slavery wasn't considered as immoral as today 200 years ago". Very different stake.

[brigandish]

The text is more convenient that the alternative.

[throwaway290]

But surely now we have the absolute knowledge of what is true and good! /s

[MichaelDickens]

Slavery was wrong 200 years ago; it is still wrong today. What changed is that the wrongness of slavery became more widely known.