Whether using the word "loyalty" to describe a dog is anthropomorphic depends on the expectations that are being attached to it. Definitionally the shoe can fit. And I actually think that the reluctance to describe individual dogs as unloyal ("disloyal" is a little different because it implies a deliberately broken bond of loyalty, and nobody's dog ever signed that contract) is more plagued by idealization of canine nature than using "loyal" is.
I don't really consider most dogs loyal enough for it to be worth remarking upon. Most dogs will show affection and attention to the people they're with most often or who give them the best things - attention and affection aren't necessarily "support and allegiance", though. And there's nothing wrong with that. I don't really know that I consider myself loyal, either, and I'm much more culpable than a dog, so far be it from me to demean an animal for its personality. In fact, I'd say they're probably on par with people as far as prevalence of "loyalty" in the remarkable sense - most are more social than loyal, somewhat loyal, not really reliable about it.
By contrast, there are some dogs - like a cocker spaniel I once had - that will bond with a given person or people and maintain that bond even if said person or people are not (or are no longer) their primary caregiver or trainer, who are unusually attuned to an owner's emotional state and seem to comfort them with more deliberation, who will come out of character to protect their people insofar as they're capable, who will go to pretty massive lengths to be with their person not because they're a fearful animal but seemingly because it's lodged in their brain (in some vague doggy way) that that's what they're supposed to do. Those are the dogs I'd call loyal.
I should have known I could count on Liminal to break it down to the most granular possible explanation!
Particularly discriminating between "unloyal" and "disloyal" is extremely relevent.
Based on your explanation of loyalty, I think that of course, who wouldn't appreciate a more loyal dog, a dog who would love them even if someone else was feeding them and looking after them because there was a genuine and deep bond.
In that sense, and in the sense that @AmandaNola explained, I do actually feel that Layla is loyal. I was thinking about this a lot on my bike ride home today.
THIS!I guess the only way I can sum it up is Nola is MY dog. No question, and it's visible to anyone. My other dogs (save for Pike, but that's because he's...Pike), while they are my dogs, aren't mine in the same way she is. She's my dog, and I'm her person. It makes sense in my head.
Layla would not rescue me (or likely try) if a bear attacked me. She's my baby and I'm her mommy (reminds me of the comment that @Rileysaur made actually). She's definitely extremely reliant on me, for food and caring and protection and everything. But I do believe our relationship is just as much about her being my baby and me being her mommy, as it is about me being the one who feeds her and walks her. I feel VERY confident that if I rehomed her, she'd have a very hard time adjusting and be quite depressed for a pretty long time, even if she did bond with someone else. I actually imagine that she would bond quickly with her new person, because she'd be very vulnerable and needy, and she's incredibly people-oriented and really needs closeness with someone who she can trust. But I also know that it would be massively traumatizing for her to lose me.
Come to think of it, I also really feel that our relationship blossomed enormously when I began using non-aversive approaches with her. I definitely think one could argue that using training approaches that build trust and closeness can actually increase your dog's "loyalty" to you. Yes, I know that abused dogs will still turn to their owners but to me that seems far more akin to the way an abused person relies on his or her abuser for direction. I think it would be interesting to see what would happen if a dog in that situation was rehomed and trained differently by a person who truly treated it right, and then a year or more later saw its previous owner again.