Who says allowing them to put anything they want? They would be subject to all local laws an ordinances like anyone else.
okay.
Are you okay with iran buying up a shitload of land in NYC and building "schools"? where they teach explosives or anger or anything else?
Are you okay with Russia buying up land and just plain loading it up with thousands of people, which can be turned loose for whatever nefarious purposes at any time?
Are you okay with mexico setting up "understanding centers" for their illegals to hide?
Are you okay with any other legal albeit potentially dangerous shit like this?
Are you okay with china hanging their flag all over your city - so the debt can be 9 tril instead of 13? I mean, really?