Is it your contention that Google should never hire anyone born outside of USA or without USA citizenship? Do you realise how much of their workforce that would preclude?
In my example, the US won’t grant security clearance to a foreign national. Even if you are a permanent resident, you don’t get clearance without citizenship.
Presumably it would only be required to work on extremely sensitive projects with national security implications (no idea if that applies in this case).
Of course not. However there should certainly be a risk assessment with regards to citizens of foreign countries known to steal IP or otherwise perform hostile actions.