I think in most cases the average is more important in deciding how much to discriminate. But I deleted the relevant phrase because I'm not sure about that specific case and my argument holds about the same amount of water without it as with it.

EDIT:

Perhaps the downvoter(s) thought you only presented the anti-discrimination side of the issue.

Huh, I was intending to say that it's acceptable to discriminate on real existing differences, to the extent that those differences exist. Not sure how to fix my comment to make that less ambiguous, so just saying it straight out here.