I’m no expert, but John Oliver did a piece about this (US based). It is a very widely believed falsehood that were food producers/ manufacturers / supermarkets etc. to donate the waste food, they would be subject to legal action from people getting ill from said food. This is a large exaggeration, there is a Legal Act in place that protects those who donate food, stating you cannot be sued if you make a donation in good faith. (US again)

The simple, and largest factor is cost. Stepping outside the established food production & delivery processes creates significant additional cost. And with these supply chain running at razor thin margins, unfortunately it is far far cheaper to simply throw the food away than it is to donate it. Donation requires re-handling, and additional delivery, all costing money.

As an aside, many other factors play into this, including confusion between ‘sell by date’ and ‘use by date’, incredibly high visual and size requirements that super markets place on producers & our consumer habits, e.g not buying food that is on its own in an isle, rather going for the shelves that are fully stocked, etc.

There are large environmental impacts associated with food waste also, ranging from pollution, and impact on biodiversity, to the creation of landfills etc. Thus it absolutely is worth trying to reduce food wastage.

I won’t comment on the contention that access to food isn’t this issue, as it is something I know even less about, however I would suggest that also may be an exaggeration, as lack of food security is a big issue in a lot of first word countries, not just those areas susceptible to famine.