How did the Nazis figure out whether a person or community is 'Aryan' or not?

They used their “spidey sense”.

Poles are “ugly, subhuman Slavs” but hey, Hermann, have you noticed how hot and blond those leggy Polish chicks look? They don’t fit our “subhuman” model at all! İn fact, they kind of look like our Aryan ideal personified!

If the Nazis wanted someone to be “Aryan”, they made up some cock and Bull story to justify it. If they wanted the opposite, they could be equally inventive in assigning someone to “Untermensch” status.

Why do women change that much more with age?

Nazi racism was not actually scientific, it was just a load of bullshit with a thin patina of “science-y” garwharbl to justify what was basically a totally ideological belief.

It was all bullshit the Nazis made up as they went along. Trying to cast it in real scientific terms is a waste of time.

And then we get sexy time with them?

What do you think of a parent telling their adult child to “keep their personal life to themselves” in relation to talking to them? No reason they should say that it was mean what should I do?

Ja, well, Helmut, it’s very simple. Those hot leggy blondes are actually not Slavs at all but are, in fact, Aryans who got Slavicised. We need to rescue them from the pit of subhumanism that surrounds them by immediately giving them Aryan status!

And then we get sexy time with them!

Ultimately, what made a group of people “Aryan” or not came down to how much they wanted them to be “Aryan”.

What are you wearing under your clothes today?