Debbie to you mean this look that the guy on the photo has? The guy is FinlandSwede with known German ancestry. The chick is a northeastern Finn.

I doubt Gypsies and Jews were never counted as Swedes AFAIK, then why would they? They have a deeper different culture and appearance.

An Icelander, a Finn and a Norwegian in Sweden is different from a Somali refugee or a MENA, many of them here since the 90s, your logic is ridiculous.. while the other three Nordic groups we share an ancient history with similar ethnic backgrounds..

And they will demonstrate that by insisting that the people with no non Swedish parents/grandparents are treated as citizens and they and other people in Sweden are only migrants. I am extending how I would carry myself among other Britons to Scandanavia.

To answer the title of this post, I would define ethnicity as a group sharing blood, a common language, and culture (religion, marriage habits, political views, etc.)
It depends how much and what kind of other blood is involved;
I would not consider a half-Somali as a Swede. I would though see how a half-Finn half-Swede is Swedish, since both groups are quite similar in origins.

Ethnicity often equates with a culture. Ethnicity over-rides race.
A guy being Indian may also be considered an ethnicity but specifically, he is a Punjab Indian/
Jewish people - they are white but there ethnic background is very much considered.