Baseball and soccer, for example, started in the U.S. around the same time . . . one became an "international" (you use that term in a derogative fashion, for some reason) and the other did not. Suffice it to say, the reason is not "leftist vs. rightist."
One cannot be an Internationalist and a patriot at the same time, it is a logical contradiction. If one loves ones country beyond all others it is then impossible to love other countries in the same manner. That is the derogatory meaning I assigned to “International.” The soccer movement in the U. S. has largely been leftist. It is not merely economics or business, or “a market!”