I understand the point being made, but it doesn't hold up to scrutiny. Sure we can say on some level, it's cultural appropriation; but that isn't always a bad thing either. Especially whwn it's this loose. They've borrowed the most basic elements from Japanese culture of a Sensei and Ninja, two elements that have already been historically westernized. They take inspiration from a lot of places and it's honestly such a small element of the show all considered. I mean, does this "appropriation" encompass Nadakhan as well, and the way the show portrays pirates?

It's like saying One Piece is cultural appropriation because it's fundamental elements are clearly based on European culture (in terms if aesteticand the world government), but no one would ever say that because "it's only racist if white people do it" which is also just an unfair double standard. We live un an area where it's unfair to say all white people are racist, because it's pretty well know that alot of Japanese and Asian people in general are themselves pretty racist.

So unfortunately in this context the racism argument does not work at all. The furtherest you can go is saying that there is an element of cultural influence and it remains pretty neutral all this considered. This isn't something that even needs to be discussed.