It wasn’t so very long ago that some Americans held people as slaves, other human beings as their own private property, as if that person were a horse or a chair, to do with, to use, abuse, exploit, beat, and rape as they pleased. What’s more, until the late 1840s most Americans thought that slavery was acceptable. The great majority found themselves somewhere along a spectrum that at one end actually exalted slavery as a positive thing, a benefit to black people they deemed radically inferior, and at the other end said, Well, it’s a real shame, and I certainly don’t condone it or want it where I live, but what’s done is done, and I guess it isn’t the worst thing in the world, and anyway there’s nothing we can do about it now, so that’s that. And in between those two ends of the spectrum rested any number of justifications and rationalizations that people used to explain, excuse, praise, rationalize, or simply accept the reality of human bondage in their nation.
Black slaves had been owned and held in every English colony prior the Revolution and in every U.S. state after it, the practice only ending for good in the North during the 19th century. Indeed, before the sectional crisis that began to emerge in the 1840s, the acceptance of slavery was so widespread that there were even a small number of black slaveholders, free blacks who themselves had purchased a slave or two.
Yet here we are, in our post-civil rights world, and we find the idea of slavery to be repugnant, horrific, and wretched. How could our ancestors have found this acceptable on any level, much less have engaged in it (Obviously I’m speaking as white person here.)? So it is left to us, as future generations, to try to make sense of it and, inevitably, to judge it. To 
cast our squinty gaze upon them and say: What the fuck. How on earth could you have been so incredibly fucked up? I just don’t get it. You people were fucking monsters.
Or there’s the whole process of murdering Indians and stealing their lands. Let’s judge that one. Pretty easy from this distance, huh?
What about the Holocaust? Care to take a whack at whether that was really, really wrong? Go ahead. My money says you’ll agree that it was.
I study the past. It’s what I do for a living. Like any historian, I try to understand the past in a historical context and on its own terms. But as a human being, I inevitably use my own presentist sense of morality and ethics when judging it. And here’s the thing. Slavery and genocides, those are easy for us now. Yeah, super wrong, we get it. But who would you have been back then, in the moment? We all want to believe that we would have been the person working to free slaves through the underground railroad, or living peaceably with Indians, or smuggling Jews out of Europe. But guess what? You wouldn’t have. Or at least, it’s not very likely. No, odds are, you would’ve been some douche bag who justified it with mealy mouthed excuses, or laid low and avoided talking about such unpleasantness. Why? I’ll tell you why.
Because when crazy shit is the norm, the lunatic fringe are the ones who embrace the right choice. If crazy is normal, then the right answer seems crazy. I’ll say it again. If crazy is the norm, then opposing it seems crazy.
So let me ask. Are you crazy? Are you on the fringe? I mean really on the fringe?