Suppose S is the set of all people.

The powerset of S is all possible ways to subdivide humanity into groups of individuals.

Comparing two members of the powerset of S is comparing two groups of people.

Any criterion by which you can divide people will produce elements of the powerset of S. For example, "people that like jazz" are in there. So too are "people who eat peas with a knife". I am saying that there are many ways to lump people into buckets. What defines the buckets does not matter. They are all in the powerset of S.

If humans are equal, then comparing any two arbitrary groups in the powerset of S should always conclude in equality. At least in some statistical sense.

I am giving a counterexample to equality across arbitrary divisions of humanity (members of the powerset of S). I claim that arbitrary groups of humans are not equally tactful. Because if you measure the tactfulness of any member of the powerset of S where I personally am present it will generally show less tact than members of the powerset where I am not present.