[Camron Rust]

One would expect that the number of selected officials would, over a small period of time, tend to reflect the makeup of the population of officials within the relative group.

If the number of capable officials were split 50/50 among two demographic sets, you'd expect to see a, over a few years, a roughly 50/50 split among those demographic groups of those actually selected. It may not be exactly 50/50 but anything that skews far from that suggests preferential treatment (aka discrimination). The more it deviates from the expected averages, the more it looks like discrimination. Said more directly, if one gender/race makes up 20% of the group of officials, you'd expect that about 20% of the playoff assignments might be filled by that gender/race.

And it doesn't really matter what the makeup of the players are, they're not competing for the assignments. It is apples and oranges. There may be other reasons to make certain decisions along those lines, but that is a different matter. And if you want to open up that door, you could argue that the players don't reflect the makeup of the overall population so the players should be rebalanced to actually represent the population .