It's a romantic post, hence the references to all the fictional depictions of pickpockets. It's very much of a piece with the heroes of caper films - people don't normally root for crooks, but the idea of a nonviolent, clever crook who puts a lot of work into perfecting what he does appeals to people.
I mean, sure, if it were being replaced with more violent thievery that would be bad, but crime has been dipping across the board.