What? In my experience, Germans don't refer to their ethnicity as German.

Besides, what if they are mixed race? Those who claim to have German ethnicity certainly could be other than white.

Quite a surprising take there @DeathArrow ...

Wrong. German is a nationality, not an ethnicity, except if you take an opinion of a few far right borderline Nazi German parties.

German is both nationality and ethnicity.

There are ethnic Germans outside of Germany. For example, Germans in Kazakhstan, they report their ethnicity as "German", despite being Kazakh citizens.

Not in Germany. The legal system here knows only about nationality, and that’s either German or foreign. And saying “Deutsch” / “German” has a prevalent meaning of a German National, eg a holder of German citizenship.

And people of German origin in Kazakhstan or other post Soviet states are referred as Russlandsdeutsche, or German Russians, not Germans.

Only far right groups insist on blood theory and ethnicity as a concept.

In daily life maybe, but doesn't mean that German ethnicity doesn't exist, see Law of Return, where the state quite explicitly judges on who is German or not, based on ethnicity.

I know a few Germans whose ancestors were from Volga and who lived in Kazakhstan, they were able to claim German citizenship by the virtue of the state considering them of German ethnic descent (they never had German citizenship before).

I am from Kazakhstan, and the Germans who live there are pretty much Russians, yet the German state still would allow them to "return" by the virtue of their ethnicity.

The ability to pull nazis out of thin air never ceases to amaze me

You are confusing Europe with the US, Canada and Australia.

Being German is akin to being Maori or Aboriginal.

I think you mistook German for Germanic. German means citizenship in Germany, Germanics were peoples living in central Europe and Scandinavia https://en.wikipedia.org/wiki/Germanic_peoples

German is also ethnicity, as I mentioned above, there are Germans e.g. in Kazakhstan and other countries, who are not German citizens.

How can it be an ethnicity when Germany itself was founded out of the leftovers of the Holy Roman Empire in the early 19th century? You might have an argument for some of the constitute elements like Prussia(ns), but even that's a stretch.

German ethnicities existed before and outside Germany, it is not the same as in the US, where Americans didn't exist before it was founded. In Europe peoples' ethnicities are not tied to the state the same way as it is in the US.

For example, Volga Germans (https://en.wikipedia.org/wiki/Volga_Germans) were Russian subjects who lived outside of Germany; Baltic Germans as well.

More examples - Hungarians in Romania, Turks in Bulgaria, and so on.