Among the dumb ideas floated by the story (and by British law-and-order types) are: Wearing hoodies is a new phenomenon (no), hoodies have a causal relationship to crime (no), hoodies are symptomatic of some new social unease (no), and Slate is a reliable source of social analysis (definitely not).
Writer Bryan Curtis begins and ends the piece with nifty anecdotes about cowering in fear of various hooded youths in London and New York. With his girlfriend in tow. Just goes to show that if you invent boogie men, you can make a good living as a writer, but at the price of your manhood. And that's a theory worthy of Slate.