Finding one person who believes something doesn’t mean anything. For starters, trolls and contrarians exist. More importantly, an isolated few doesn’t equal a meaningful plurality. You can find Japanese people who hate Japan and want Japanese culture to be utterly destroyed and replaced. How do you think they feel about a disruptive black main character in an historical video game with a traditional Japanese setting?

There’s really no point in engaging with people before firmly establishing first order principles. If you’re debating someone whose central premise is the total annihilation of your people, your culture, and your nation, then you are wasting your time. You should be focusing on destroying them in kind.