Okay, you've explained that well, thank you. Learning how people behaved (and how it led to our behavior) is not the same as merely looking down at earlier generations to boost our self-esteem. To me, that's the equivalent of tourists making fun of people in other countries.
And I agree that understanding why people thought a certain way is not the same as condoning it. Hopefully, looking back will give us a certain perspective on where we are now... and make us wonder where attitudes will be another generation from now.