I find it funny that Europeans get so offended when Americans call soccer... soccer. We just use the original name for the game, not the new fancy name like Europeans.
"Football" was associated with "Rugby football" otherwise known as "rugger". Rugby and Soccer were both being organized at this time. The name of soccer/football came from unifying the rules under 'Association Football' in the 1860s which was shortened to “Assoccer”, which quickly just became “Soccer” and sometimes “Soccer Football” but not "football" by itself until 18 years after the sport had been in existence.
Rugby and Soccer were gentleman's sports played by the upper crust of society. Eventually both sports would be start being played by the lower classes. However Rugby didn't quite take off with the lower class like Soccer did. It was at this point that “Soccer” and “Association Football” changed to "Football" among the lower class and remained “Soccer” and “Association Football” among the upper class.
The first use of "football" alone referring to this sport appeared in 1881. 18 years after the name was officially “Association Football” and commonly referred to as “Soccer”. The sport spread by means of the lower class who called it "Football" but this didn't work so well with the United States, Canada, Ireland, Australia, New Zealand, and South Africa; among others whom already had existing sports called "Football". As such these nations used the upper class and official term of "Soccer" so as not to confuse the two sports.
If you wonder why American Football which is mostly played with the hands is called 'football' it's because the game is played on foot. While most but not all upper society games were played on horseback, lower class games were played on foot and were thus classified as 'football'. This term had nothing to do with how you interacted with the ball; and even basketball would be classified as 'football' under these terms.
The United States originally unified under the "United States Soccer Football Association” but in 1975 shortened it to just soccer.
BTW here's how Americans see Cricket.
[flash]https://www.youtube.com/watch?v=dEH4ahCCrJo[/flash]