It's just a passing fad, nothing more. Football's at its least racist when nobody's talking about race. It's a bit like referees really, the ones you notice are the attention whores.
The truth is that within football grounds, every one for many many years, there has been the odd bloke shouting racist abuse. I have heard it at OT from reds about united players in the past. The real problem is when the players, staff or managers start doing it!!! They are on tv most of the time and are meant to be "role model" to kids