Why are people who know very little about Japanese culture trying to argue about it?
If anything it's further reason why you shouldn't be making something if you don't have an existing background in it. Just makes you look silly to people who actually know what they're talking about.
I can't believe that now people are trying to spin Japan off as some super progressive hotbed of diversity.
The thing is, I don’t know why you have to understand Japanese culture if you’re writing a manga.
If you’re Specifically writing a manga, where the story specifically revolves around Japanese Culture, yes, you need to understand Japanese Culture. But a manga doesn’t need to have an connection to Japanese history.
But manga is literally just a Japanese equivalent of a comic book. Sure, it has a different art style, but there are plenty of things outside of Japan that imitate manga art perfectly(The Boondocks, Teen Titans, Avatar, Castlevania, etc). And there are manga out there that is paneled, and laid out no differently than an American comic.