I feel like you guys are talking about structural pruning, equating it with aesthetic pruning. This dude at yamaguchi is engaged in aesthetic pruning - the tree is not a structural threat to anything, so he can do what he wants. The rules can change in that circumstance. Think about what you might do with a tree if you were freed from structural considerations. You could prune in codominance, thin, cut roots to kill part of the trunk, graft it to itself in a circle, grow it in form to attain the shape of a chair. It's the wild west if structural considerations are on the backburner. That's where thinning comes into it's own - in aesthetic pruning.