That was a good ten minutes of "let's teach our dogs to guard food from each other!" I wouldn't want one of those pups, that first pup just spent a good long time learning that going after dogs that approach his stuff works really well, and then the item did get stolen, so she needs to do even more next time.
It's just another person pretending they know why dogs do things. No the pup isn't growling because he likes food and wants to keep it, nope, DOMINANCE. I bet nearly all of them would have guarded the food if they liked it enough, the only reason one pup wins is because he's more persistent, wants it more than the other pups, is more confident in himself (and his ability to win) than other pups, or has learned already that making a fuss gets him what he wants (I'm sure there are other factors those are just the ones I can think of right now). The others lose because they are more interested in avoiding getting attacked then in getting the food.
It wasn't "sorting out pack structure" it was a dog guarding food. If someone said they had a dominant dog I would have no idea what to tell them, that means nothing, if someone said "my dog is guarding food from other dogs" then I have something to work with, they told me behaviors. dominance is a very useless word, at least with dogs.