Was the Holcaust more evil

... than other systematic mass murders? Sasha Volokh says no.

Take any six million people murdered. You can draw a circle around them and say, "These six million people define a particular group X," and the killing of these people is especially evil because it's the systematic extermination of everyone in group X. Of course, in the general case, there's nothing "special" about group X. It's just a somewhat random assortment of people: {Fred, Dave, Sasha, ...}. Why should the set Y = {Jews} be "special"? Only because there's something special about having Jews in the world. But "an entire people" has no moral value, except insofar as that "people" contains people. I don't care whether Jews as a group exist; but I do care about every individual Jew, as much as I care about every individual whatever-else. Corollary: Every group X containing six million people is equally valuable, and any murder of any group X is equally immoral.

I tend to agree with Sasha. There are lots of things that make the Holocaust stand out in history, but those things don't make it more evil than other systematic mass murders.