In my work, "differentials" makes some sense because I do a lot of thinking in terms of specific groupings, which I guess in that SO link would fit next to classes. I am talking about differences but in more of a logic-derived, mechanistic way compared to more usual ways of thinking about people. This helps to apply thinking that is a bit more hands-off, which is useful for the same reason that DATA was useful in ST:TNG, I guess you can say. (Not that it's super unique to think that way; certainly lots of people are capable of logically thinking themselves into gigantic problems, like Michael Larson and _Press Your Luck_)

I wish I could really do it all justice here but HN comments probably just aren't the place, anyway.