In an ideal world Man City would win every game 5-0, the supporters would all stay til the end to clap the team off and that the songs sung in the ground are all of an Edward Elgar type quality with only pro-city sentiment.
Yes the chant is simple,
Yes the chant mentions United Staff
Yes the chant mentions a taboo subject.
Yes some people would deem it to be offensive
The problem with offending someone is that everybody has different boundaries on what they would deem offensive. Unfortunately the way society is heading is that a day will come where we will all have to live our lives by the standards of the most easily offended, when in fact they probably represent such a ridiculously small proportion of society.
To take an example, think of a joke that really makes you laugh, then think about whether that joke is mocking or scapegoating something, what if society then deemed a joke like that too offensive, to the point where it is illegal to tell it. Do people really want to be heading in that direction in society?