"Ethical eating" is a reaction against a wasteful society—highlighting how supermarkets dump tons of food every year that is still edible. In the United States, dumpster divers see their lifestyle choice as a way to protest against terrible waste. Some food has "expired" but some is still "in date." Some argue that freegans are hypocrites and are essentially stealing from stores. If they bought the food in the first place, detractors say, they would lessen the waste, not contribute to it.
Source: Bbc.co.uk