Not sure how you argue that discriminating between two people based on age is not age discrimination. It just seems illogical to arbitrarily ascribe value to age, especially to a greater age. The guy that's hired older is probably older because a) he elected to extend employment elsewhere for some perceived benefit, or b) he wasn't as successful in his career as a younger candidate.

If you're going to do it by age, then why not reward the younger guy, for getting there earlier in their career? Or pick the guy who did the best on his cognitive tests?

I would have done poorly with either an SSN or age, so this isn't a personal issue for me. I simply find the "older deserves more" argument somewhat odd.