> especially since the US is the only country that has this

I see this said in real life as well, but it's just false. Plenty of countries in North America do this, including Canada.

https://en.wikipedia.org/wiki/Jus_soli#North_America

> Canada: Subsection 3(2) of the Citizenship Act states that Canadian citizenship by birth in Canada – including Canadian airspace and territorial waters – is granted to a child born in Canada even if neither parent was a Canadian citizen or permanent resident except if either parent was a diplomat, in service to a diplomat, or employed by an international agency of equal status to a diplomat. However, if neither parent was a diplomat, the nationality or immigration status of the parents does not matter.