If what they are planning on building is as important as they say any edge US can get it should take.

Having a large number of individuals who are not loyal to the country that provides this opportunity is a future threat the moment an advesary cuts a check.

If this is the nuclear bomb of our age would you want a large number of foreigners building it for you? If this action sticks I imagine every country will follow the same path and treat top AI scientist much like a top nuclear engineer.