I can have my dog out early for a good, long, desperately-needed first thing in the morning pee, but he will still with-hold a considerable amount of "ammunition" for the walk. Male dogs have voluntary urine control for territorial marking. And the more territorial the dog, the more dedicated he is to his vocation. My dog makes his ammo last for the entirety of our regular walk! He only runs out if we go a bit further. We call it reloading or tanking up when he drinks water after a walk.
I think most people know this about dogs through simple observation and basic familiarity with the nature of the species (protective, territory-holding animals, highly social, descended from wolves, "see" the world through smell). Our culture normalizes these things and accepts them because we value dogs as companions. Other cultures reject dogs as companions specifically for these factors. Cranky poster is just born in the wrong place, not Freud-worthy.