The whole racism thing at the City game is lamentable but not unexpected. It's endemic of not just racist views among a small but vocal minority of fans, but also of a general strain of petulance and spoilt brattish-ness among the City fanbase. For the first time in 3 years they are not blowing everyone away on the pitch, picking up all the domestic trophies. They don't look solid enough at the back or prolific enough up front to get their hands on that highly coveted Champions League cup. And if results don't improve in the league (especially if things keep going well for United), they could be battling for 4th place with Chelsea and Man U in about 12 weeks time.
The ones outing themselves as "racists" are exhibiting the typical behaviour of the childhood bully who suddenly feels insecure and finds it hard not being top dog anymore. Overt and violent racism is nothing more than a lazy, puerile way for people to voice their displeasure with their own personal circumstances and society in general. The immigrant, the outsider or the person who is obviously of a different race is an easy scapegoat, an easy target on which to project their own sense of inadequacy.