I would guess that many, if not a majority of the rioters lack a credit card, and quite possibly a registered permanent address for deliveries. These are people on the farthest margins of society, often with very little to lose.
Therefore I'd agree with mortenjorck, the majority of the rioters probably don't have credit cards and probably aren't the kind of people who order stuff from amazon.
There are political issues at hand, even if the rioters themselves aren't aware of them.