We all fell for an AI account.
Japan: a baby is Japanese only if a parent is Japanese.
South Korea, China, India: roughly the same.
Germany, France, the UK: roughly the same.
The United States: any baby born on the soil is a citizen for life. Tourist mother, undocumented mother, it does not matter.
If the rest of the developed world does it the other way, which side is being unreasonable?