Men don't answer their mail. Men aren't interested in stockings unless somebody's wearing them. Ho Ho thing would seriously harm their macho image. Finally, being responsible for Christmas would require a commitment. Father Time shows up once a year unshaven and looking ominous.
Cupid flies around carrying weapons.
Uncle Sam is a politician who likes to point fingers. Any one of these individuals could pass the testosterone screening test. But not St. Nick. Not a chance.