Per the article, they exist elsewhere, including elsewhere in the US. Most European cities don't typically really suffer from the problem that New York apparently has (where groceries in New York are apparently significantly more expensive than outside, and significant areas don't have proper supermarkets at all). If they did, in many countries there would absolutely be some sort of intervention.
Sidenote: Has there been serious research into _why_ these 'food deserts' happen (or at least their urban form; the rural version seems more explicable), and/or why they seem to happen in the US more than in other developed countries, does anyone know? On the face of it, even as a fairly market-sceptical person, this is one that I would kind of expect the invisible hand to deal with.
99pi has a nice podcast on food deserts. It puts the blame on the decision from the FTC to stop enforcing the Robinson-Patman Act, and only use consumer prices as the metric for antitrust rulings.
