> The requirements are essentially that you're either upper-middle class

Not true - a youtuber from Germany who lives in Japan since about 10 years, was denied citizenship recently. And he'd make more than enough money.

https://www.youtube.com/@NihonGoo

The thing is really true: Japan is against more immigration. You'll always be a gaijin there if you come from the outside.

> there seems to always be a large number of clearly white people from America and Europe coming in to display their Japanese nationalism

Other countries are also very much against mass immigration. Japan just does it in a very strange way.

You're misunderstanding the immigration requirements: who is considered doesn't necessarily mean everyone that fits the requirements will be accepted. It's a requirements list for exclusion, doesn't say fitting the requirements implies inclusion.