Yes! I was referring to that same picture! I was having some difficulty explaining the concept of cultural appropriation to a friend so I just asked her to read your comment on that post and she finally understood. Btw, I think matcha is actually from China! However, the matcha tradition was lost there over the centuries, whereas it became stronger in Japan.
Technically almost all tea can be traced back to China via India, so that discussion isn’t new. While the Chinese likely did pioneer the concentration of green tea leaves into a powder, it was the Japanese who placed it on a pedestal and made it a central part of (what started as) a religious ritual.
Japanese history has had a fun habit of taking things that the Chinese discarded as boring and making it their own over time. One of the best examples is oshiroi itself (and certain ways of applying make-up) that the Chinese felt was out of fashion by the 8th century, but to the Japanese nobles it was the best thing ever. Here we are thirteen centuries later and certain parts of Japanese culture are still using oshiroi ^^;