Answer :
it could be that since time continues, so does people’s beliefs and what they think is right. as time goes on, we are making and starting to believe in new and different things than what we did say 50 years ago. so, for example, when white people owned slaves, back then, a lot of people saw them as “heroes” because they were doing the acts that they believed were right. now, nobody really likes slavery, with some exceptions of course, but when someone mentions white supremacy or something like that, we automatically don’t really like them, because of what we believe in now.