A few good points made above. I think ignorance has quite a bit to do with it. Couple that with a limited education, tribal mentality and copious amounts of booze and voila.

I shall be watching the Champion's league final between Manchester United and Chelsea in the comfort of my home in front of my own TV with a large bottle of Perrier sparkling water and a large bag of Miss Vickie's Jalapeno chips. Come on you reds.