It's a blog about Japanese food which is why they're talking about "Japanese techniques."
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.
This should be the top comment. It's like criticizing a tutorial page on pythonguy.com titled "Python techniques for copying data structures" because the author didn't explain that the same techniques are used in Julia.
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.
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.