Exactly. Every time the UN does something, people say “they can’t enforce it”.
Well, that’s the whole point of the UN. To resolve things without using force.
It’s a good design, designed by people who learned from the horrors of WW2.
It’s sad to see how many people nowadays forget those lessons and are itching for global war.
Also, having been on the other side of such a situation: it’s not cool to pressure or guilt trip your guests. Either be hospitable and let them do whatever they want, or don’t invite them.
If people aren’t hungry, then they aren’t hungry. Maybe they are on a diet, maybe they misunderstood OP’s intention and ate beforehand. Maybe they are recovering from something and don’t want to eat too much.
And as for the two that did not showed up. It’s a good practice to reconfirm the night before. Sometimes people forget. Sometimes life gets in the way.
If they did reconfirm and still didn’t show up and did not have a good excuse, then I would start looking for better friends.
Hope OP has better success next time. I do understand that the situation sucks.
But it’s also a situation that, in my opinion, is preventable.