these guys need to get laid pronto. such a bad mix of non-education, boredom, aggression and sexual austerity makes any man freak out in all kinds of ways. being a guy in islamic countries only rocks superficially, due to the massive youth bulges most nations have accumulated the chick-ratio is just too subpar for society to be even-tempered.
It's a bit of an oversimplification but fair enough. Lack of education, jobs, sex, hope or whatever is still no reason to go to sports games with the intention to beat people up. Doing it and then actually kill people medieval style then we got a new level of madness.
Like most riots it has more to do with "pack mentality". They pump themselves up into a frenzy and if there is nothing or no other force to hold this frenzy back it will boil over sooner or later and people just follow without thinking. All it takes is those 1-5% if total idiots that take it too far and then usually others in the pack join in.
That is where this failed. The security/police or whatever must act before it goes too far. But with the state in Egypt and also the kick some young lunatics got out of the revolution they have surely been looking for more of that action. It's gonna be a major problem for Egypt to handle these young males that think they can do anything after being involved in some recent success