Not very unique to Japan. You can also see these techniques in other East Asian countries like China, Korea. Japanese guys are good at promoting their cultures anyway.
This article places the shapes or cutting techniques described within the context of Japanese cuisine. That someone somewhere else has at one time or another cut a vegetable does not really reflect on the formal techniques of a cuisine whether that be French, Chinese, Italian, Korean, Japanese or other cuisines that put a significant focus on defined techniques and following specific processes.
Maybe readers are inferring some nationalistic element to a cooking tutorial, where people assume that a description of techniques used in Japanese cooking is some kind of claim to ownership of them?
I think this article is interesting on its own terms, because regardless of your heritage, if you haven't studied cooking you might not have experimented with how you cut vegetables. I always used to just straight chop everything when I made a stir fry, but now I try to be more creative.
As for techniques, my favorite is cutting a minimal slice off of round items (think onions) to use as a flat stable bottom before attempting thin slicing.