Nope, it's nothing to do with religion or lack of it.
It's about a "bling" subculture that has grown up over quite a few years, usually amongst disaffected youths who have no qualifications and jobs, and no sort of work ethic. They often live in deprived areas where drugs and gangs are a problem.
All the atheists I know are hard-working and stakeholders in society, and are the antithesis of the sort of thugs who are doing the rioting. They're more likely to be the ones who have the businesses being wrecked, though thankfully I know of no friends affected as yet.