used to dumpster dive a bit when I lived in a punk house that had touring bands every week. we got caught by an Aldi employee and ever after they slashed all the bags of perfectly good veggies etc and poured bleach into the dumpster.
If you haven't worked food service, be it in fast food or a grocery store (I've done both), then you truly do not understand how much perfectly usable food is thrown out DAILY in service of the idea that Some People Don't Deserve To Eat, an idea that underpins our entire God damned society.