It was in the context of riots elsewhere in England -- if you read the whole article, there was a nationwide directive to treat rioting related incidents far more harshly than is the norm. (I'm not defending this!)
Some other examples from the article were jail sentences for small thefts, such as a single bottle of water. Like stealing a bottle of water, calling for a riot (regardless of whether anyone shows up) is a crime. The real story here is the general pattern: harsh prosecutions for crimes that would normally be forgiven.