I'm not sure about the listed facts... I opened up Helsinki where I live, and got this: "Every residential building has a sauna -- it's not a luxury, it's basic infrastructure, like having hot water."
Certainly it's very common, but certainly not "every" residential building has one.
I looked at some other cities I know a bit. Those "facts" are typical AI slop. Not always completely wrong, but stereotypes you will easily find on the internet.
Certainly it's very common, but certainly not "every" residential building has one.