In the early 20th century, American 'football' included much more kicking and very little throwing. It was mostly running and tackling with kicking as a main tactic.... so 'football' was a better term than 'runball'.

English/European football was barely known here till after we all got 'better acquainted' during WWI & WWII. Thus, 'soccer' was simply a convenient term to distinguish the topic.. there is little confusion about which game is meant, even when certain parties object to it.

We in America have a very low participation in forms of Rugby and Australian football, and no sports discussion which begins with the word 'football' will have to define terms.

Sarcastic complaints about which sport really deserves the name are silly, as it is only in places like thread titles in forums where it needs clarification.