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

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.

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!

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!

How will the article end in Part III of Gleissner's hit piece?

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.

And then we get sexy time with them!

They used their “spidey sense”.

Predator: Killer of Killers Ending Explained - Does It Set Up Prey 2? - IGN

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

And then we get sexy time with them?

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.

What do men find attractive in an older woman?