I'm puzzled by your response. You list some stats about waste and that justifies what the guy is doing? Of course it's probably hyperbole but people are working hard to defend this guy's statement.
It seems like a growing number of comments on Hacker News are of this virtue signalling, amplify the problem but offer no solutions variety. This is not the hacker ethos.
The hacker looks at your parent and says woah -- grocers throw away 30% of food? There's a startup opportunity. And when they succeed they accomplish more than all the hand wringing in the world about someone else not doing their part.
I think even bigger is the 10:1 gains or more you lose feeding crops to animals. If we all went vegan we would almost instantly double our food supply.
It's fairly normal. In the first world, we waste a lot of food because consumers can afford to be picky or forgetful. In the third world, they waste a lot of food because storage and distribution infrastructure is worse.