This concept is relevant because we learn from those around us. And so we need to be mindful of what we consider normal and acceptable behavior. By studying different times, through the perception of our sages, we gain a clear standard against which to judge our own generation. And we come to recognize that what we see in the world at large isn’t normal – and it certainly isn’t acceptable.
We need teach our children that this isn’t the way. Just because it’s done doesn’t make it tolerable. There will again come a time when people look at such behavior with the appropriate sense of horror, shock and disbelief.