“What other suicidal nations take in foreign nationals as officers in their military?”
Israel
England
France
Just off the top of my head.
Pretty standard way of earning citizenship.
You are half right. To join the armed forces, you do not have to be a citizen, just a legal resident.
To be commissioned as an officer, you have to both be a citizen and be able to gain and maintain a SECRET security clearance. Which implies having spent around 10 years in the country beforehand so the investigators have enough info to make an assessment.
It’s not like he got off the plane and went straight to the recruiters to become an officer.
Lots of countries do. It’s still suicidal and idiotic!