How can the United States block the sale of a radio station based in Mexico?
This reminds of the late 1930's, when The Carter Family used to play over radio station XERA just across the border in Mexico which was run by a quack doctor selling phony cures for lack of male "virility".
The station was not under the regulation of U.S. laws, and therefore could blast out a signal at far more power than any station within the USA...