Moving on from the knockabout stuff - I think the origin of the term soccer and understanding the context within the game when it was coined may allow us to understand why football fans are so negative toward the term.
Remember the term arose from a public school and Oxbridge slang approach - i.e. associated totally with the elite in Britain. It was first coined in the 1890s and usually attributed to Charles Wreford-Brown, who was very clearly part of that elite (Charterhouse school, Oxford).
Now although it is not as well recognised as in rugby (schism between union-amateur vs league-professional) the same battle was raging in football at the time. In other words between those that wanted football to be a 'gentleman's sport played in a purely amateur manner and therefore only by the wealthy, as they were the only ones who could afford the loss of time/earnings associated with the elite sport and those that thought that the sport should be professional and allow working class to play at the top level. The former were linked to teams from public schools (Old Etonians, Old Carthusians etc) who remember dominated the early years of the FA cup.
The battle reached its peak at just about the point when soccer as a term was coined and would undoubtedly have become synonymous with the elite, public school, amateur, gentleman game. Indeed Wreford-Brown was apparently the leader of those trying to ensure that football was amateur and the fiercest critic of those trying to ensure the game could be professional. So he would, undoubtedly have been a bogey man, a figure of hate to those that felt he was trying to prevent the game being widened to the working classes, and in particular the northern working class clubs as he really wanted the sport restricted to the southern teams that were linked to public schools, universities etc and wanted it to be resolutely amateur (in the manner that rugby union was for decades).
Now those from the professional 'side' associated with clubs embedded in the working class areas won the day (and the public school clubs vanished from the elite game). At that point the game became a resolutely working class game, with the public school elite largely disowning the sport and shifting to rugby etc.
Given that background it is not surprising that even back at the turn of the 19th to 20th centuries the majority of football fans (supporting as they did the professional working class clubs) would have seen those, including Wreford-Brown, as bogey men and therefore hated the term that was inextricably associated with the public school elite who had tried to prevent their clubs from succeeding and had wanted to restrict the sport to a small public school, elite. And of course that term was soccer.
So a brief glance at history explain why, even decades ago, football fans have always used the term football and be deeply suspicious of the term soccer. And that attitude remains to this day, albeit there has been a shift in the focus of the negativity - away from people trying to restrict their sport to a public school elite, but rather a view that the term is american. But actually a theme does remain - a view that those that use the term soccer in Britain do so in a derogatory manner, effectively looking down their nose at the sport, exactly as Wreford-Brown did about the professional game all those years ago.
