The best we can do is admit it was wrong and we aren't infallible, have empathy for others on the same path, and help them see what we see. After all, only a few generations ago it seemed like the natural order of things. If only 10% of people disagreed, how sure would you be that you land in that 10%?
Stepping back to today, what practices do 90% of us engage in which our children's children will look back at us as barbaric? Statistically it doesn't look good for us.
American didn't abolish de jure slavery until 153 years ago.
It retained de facto slavery for much longer, as it did little to enforce the prohibition on except terminating overt chattel slavery until WWII (the federal order to federal prosecutors announcing the policy shift that stopped eseentially ignoring this was issued five days after Pearl Harbor, 77 years ago.) [0]
I don't believe the point is particularly changed though.