In a hand-washing, sanitizer-carrying culture, why is it acceptable to lick one's finger before separating a sheet of paper to hand it to someone?

By this I mean when someone licks their finger to better grip a sheet at the top of a stack of paper to more easily separate it from the others?

And here is yet another post of yowen, spaghetti and meatballs, wondering why in the hell something is the way it is. I spend a lot of time on a daily basis wondering about these menial things.