I honestly don't understand what you mean. I am not american, the only thing I can maybe see is the fact that the characters are indeed too forward thinking for their time period, but that was the point?

She did grow up in the us. The producer is also asian. As for the rest of your message, you are entitled to your opinion of the show of course.The show never intended to be 100% historically accurate, quite the opposite

It's so interesting that you said that,considering that one of the 2 makers of the show is literally Japanese/White, exactly like the main character Mizu. It took one google search to figure that out