As fetishes go, this one seems almost . . . positive. Like people who prefer overweight people. Sure, it goes against society’s grain, but as long as we’re talking responsible consenting adults here maybe some of our olderly types deserve to be treated like they’re still sexy sometimes, right?
The sexiest part of us is the mind, after all. I know some old people who have AMAZING minds!
More power to them, just so they get to come out of the closet and all is Safe, Sane, and Consentual. 
note, I know that’s now how you spell ‘consensual’, but I’m protesting the stupidly modified word. Seriously, leave the T in there.