Why can only one 1933 double eagle be owned legally?

The U.S. mint in New York in 1933 banned the legality of the coin any of them owned that escaped re-melting were deemed as illegal except for one coin own by at the time King Farouk of Egypt who wanted a exportation license on one of the coins BEFORE the New York mint deemed it illegal. Thus because of the exportation license and its LEGAL admittance of ownership, there is only one 1933 Double Eagle coin that can be legally owned. Any other ownership of a Double Eagle coin would result in a immediate investigation and confiscation from the secret service.