I work in retail. Stuff already goes to food banks. The dates on those products are usually the sell by date, and quite arbitrary. They're mostly for quality sake, rather than "not safe to consume" sake. Like a loaf of bread may not be as moist and soft as it was when it was fresh, but it's perfectly fine to eat. Companies want you to be able to buy a product and expect consistent quality. But if you're hungry and in need, stale Oreos are better than no cookies at all.

I mean, to the last bullet, we have good Samaritan laws. We could totally pass a law that says "grocery stores can and should provide reasonably safe, leftover food to poor people and will not be punished if those reasonable actions result in bad things happening". You are allowed to just wail on an unconscious dudes chest for minutes until paramedics arrive and then not be sued for the three cracked ribs.

But cmon. We all know that grocery stores know that once people realize expired food is generally safe a) people will buy less food and b) people will show up to get free expired food and buy less food.

Scarcity is a necessity under capitalism. Movie theaters aren't going to release blooper reels for free. They add them to the credits or put them in the editors cut release. A luxury clothing brand isn't going to sell seconds, they will destroy or rework material that isn't sellable.

A note: stores throw out unexpired goods all the time.

As for food safety, yup, that's important. Some goods could be too risky, like raw meat. But so so many goods are processed and stay good long past the expiry.

Expiry does take into account oxygen. Once you open a bag, air gets in and then it could get stale, mold, etc. If it has been sealed in its package the whole time, there was never any (*a lot of) air to start those food-ruining things.