Yep, he originally threw out all names that appeared on both lists, while he's now arbitrarily assigning them to the winners' set. Not sure about the reasoning behind the change, but there it is. The quoted line computed new winning and losing sets that excluded all commonalities.
I actually also really liked that line, it helped flesh the article out to be an impromptu tutorial on using sets in python (which it still is, to a certain extent). I remember reading that sets overloaded some sensible operators a while back, but I really appreciated this reminder.
In other words, very nice of you to highlight it in a comment, as new readers wouldn't have seen it otherwise (as it turns out).
