Soccer balls are also thrown with the hands, bumped with the knees, hit with the head, and caught with the chest. Not very foot-specific if you ask me.
Imagine claiming someone has a complex and then claiming to represent the world and its ownership of a language. He simply is pointing out that American English has been distinct since it left “Great” Britain in 1776, and that there is no longer any ownership of the way Americans speak by the British “empire”.
Also, it appears that more people call it soccer than you think, possibly even a majority of primary English speakers. See the sources on Wikipedia for further reading:
https://en.m.wikipedia.org/wiki/Association_football#Name