My parents of different nationalities had me in a third country. It would be really really shit for them (and me) if I didn’t share their nationality. They would have had a foreign child, who would almost always go for a citizenship as soon as possible anyway.

Much easier to just give the kid a passport if their parents have one.

And since I was born in a country that DOES have birthplace citizenship, I technically have three nationalities (only two passports though, way too much work to get the third one)