So much food is thrown away by grocery stores on the expiration date or just the day after. Usually you can eat that for a few more days, but grocery stores do not want to take the risk of selling it.
The vegetables were kept in a separate wheely-bin from the skips, so it was a lot more hygienic than just diving into a dumpster with everything mixed in. The bread was also kept in separate bags, next to the dumpsters. I think that all the discarded bread and vegetables went to local farmers for animal feed.
Only a tiny subset of food is legally required to have an expiration date. In the UK this is the "use by" date. In Canada it's the "expiration date." But, you'll find this, or "best by" dates on way more products, because they want to move more product.
In the US, for example, only infant formula is required by federal law to have an expiration date (1). The same page states that: "Foods not exhibiting signs of spoilage should be wholesome and may be sold, purchased, donated and consumed beyond the labeled "Best if Used By" date."
(1) https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety...
The legality and morality of donating food past its expiration date is somewhat murky and different depending on jurisdiction. I know France passed a law specifically allowing the practice, and its at least tolerated in Germany.