Lol, Anyone surprised that people with a lack of consience steal during a riot, even from people they might have a relationship to or belong to their own community?. Whoever said these any of these guys were in it to avenge their friends death, that said if they even had any relationship to Duggan in the first place. People do this kind of thing all of the time, using confusion and situations where the risk factor of being reprimanded is very low. For people who commit theft and petty crime, pragmatic thieves and small time criminals, its the perfect situation to come out and steal during events of disorder.
I used to hang around crowds who had profiles like this. and i can tell you that easy theft was an accepted norm amongst the urban immigrant youth culture. We were all third generation immigrants from working class families.