I'd say that's a big-ole-case of "I'll show you what I think!" LOL. Dogs that pee on people are obviously giving their best at showing what they think. Their trying to dominate and show there's a misconception (in their mind) as to who's the culprit, or who's the alpha when they want to be. I think it's in defense of when they're out of their element of being a lowly, domesticated "dog" in the population of humans. It's a pecking order thing. I'm not a dog psycholgist, but I know dogs, so take it at what it's worth. I think a dog that does this is frustrated and that's their innate nature to do something about it!!! But you got to love them all the same and adjust YOUR behaviour to figure out the problem.