Yeah, based on the title this is about MAGA, but there are plenty of people more on our side who say the same things. And it's fine, if done respectfully. If you go over there, realize and acknowledge you're a foreigner, but want to warn Japan, that's one thing. That's not inherently subversive.

I do agree with OP that this seems subversive though, since it seems more aimed at interfering in their political processes than giving them advice from a place of love. Note the framing, too. The reason for moving to Japan from the USA (not that they'll even do it, probably), is that they hate the US, not that they appreciate Japan.

They're a tourist, and they need to fuck off. From both countries, ideally.