Crap. They throw away food because it's cheaper to throw it away than to give it to those that need it. It has nothing to do with 'liability' or 'regulation', given they still do the same in NZ, which has neither the concept of personal injury liability nor onerous food regulations.
Correct, even just paying for delivery to homeless shelters is the money no store owner wants to pay and even if you get volunteers they still have to pay for gas.
Edit: forget gas even paying the employees to sort the food that is still edible costs too much.