It seems lost on you that the cop already knows he's talking to a guy so drunk he's already tried to lie to his face about who was driving the cart (even tho he has been in plain view), saying his wife was, then stumbled over trying to invent some reason he was driving using her licence (as if that's a thing) until, in desperation, abruptly played the "I live right there" card.
Of course his tone would seem condescending if the person being addressed were sober, but Brunette was clearly, obviously, not. On the contrary, Brunette was ineptly trying to lie like a child, was behaving like a child, and reaching for a way out like a child with no self-awareness re the situation he was in. The cop is de-escalating confrontation by talking to him on Brunette's childlike state of mind-level while he's gathering information.
While the tone may annoy you, it worked. The situation never escalated until the penny dropped when Brunette was about to try the roadside sobriety test and tried walking away, but that had nothing to do with anyone's tone up to that point.
Again, at the very start Brunette was so out of it he actually tried to deny he was driving an open-air golf cart while in full view of the cop. The same cop he'd interacted with before driving away from the restaurant. This is a pretty sure sign that his brain was in 4 year-old mode. When you were 4 years old your parents probably spoke to you the same way but you never noticed. Nobody does.