"Soccer" derives from Association Football, from the "soc" of "Association" and at the times, the British had the tendency to add "er" to words so it became "soccer" given it an extra C for good measure. The word "soccer" is an "-er" abbreviation of the word "association" in Association Football, so calling the sport "soccer" is the same thing as calling it "football." It's practically the exact same thing.

Furthermore, isn't it completely ridiculous that the British would get so upset over us Americans calling the sport "soccer?" Like, who do you think we got that from? We got it from the British. So if you're British and you're upset over us calling the sport "soccer," look it up.