The last paragraph "They are in such a hurry to beat everyone to the food they spoil everything." has me thinking there's more to this than someone taking "all you can eat" literally.
I remember when I was a kid, my family went to an all you can eat restaurant and my sister really did take all she could eat. She ate so much my parents were worried management was going to be really pissed, but the employees said "it's fine, she really is eating everything she takes. It's the ones who take that much food and don't bother to eat it all that we don't like."