Greedy is just something that someone thinks about someone else's eating, as demonstrated by this thread.
No-one NORMAL gives a flying fuck about how much OTHER people eat. Normal people have better things to think about than watching food eating and judging food eating and counting each food item.
The ONLY people obsessed with what 'others' eat are those with food issues. Food issues are where you think about food and eating a disproportionate amount of the time. It is a mental health problem.
You watch other people eating. You judge every little thing that goes in your own mouth as well. Your whole identity revolves around eating. You think about food almost ALL the time. It swallows your waking life. You know the calories of everything - and the value of nothing because you live in your own world, and it isn't the same world as people who have a normal relationship with food.
You join in these threads because it allows you to talk openly about food, to show yourself that you can talk about it and yet deny yourself at the same time. You feel vindicated by others who are also in the grip of eating problems and you hope that that makes you more normal. Deep down you know that isn't the case.
People with food issues can be thin, fat or average. It is a mental health issue.
I have close relatives who sadly have had their lives blighted by this. I can recognise it in some of the comments on these threads, again and again, every time anything to do with eating comes up. It is so, so sad. I would plead with people to seek help - you don't have to live in the grip of this.