I was born on an Army base in Germany. Both parents were from Michigan. When I turned 18 I had two options, join the military for US Citizenship or sign a form stating I was going to be an American. You have the option when born abroad to have duel-citizenship so I could have declared I was both American and German.
I don’t think you could have had German citizenship just by being born there. They don’t play it that way. Still more into the racial business. There’s turkish families where the third generation is being born there, and still no citizenship.