There's some truth to your observations about some people's emotional attachment to pets. But you don't have to be Freud to figure out why many humans form strong attachments to pets.
Humans abuse each other, mentally, physically, we aren't exactly the bee's knees as a species. If at our core as humans all we want to do is receive and give love - what's really the difference if the heart resides in a dog or a cat?
Would you truly grieve the loss of your dog as much as the loss of your spouse or parent or brother?
Sure, if my dog showed more loyalty and love than my spouse, parent or brother?
I do think humans are more important than pets but ya know what - I can't give you a good reason why. Can you DUC?