should I care if they think it's a kid? As long as they don't or the dog doesn't bother anyone or become a nuisance, it's really not my business how they think of their dog.
I just don't like dog people that spoil and don't train them to behave, that don't clean up their messes, don't keep them on a leash in public, etc.
I've met owners with fantastically well behaved dogs that don't cause any issues who call their dog their kid. But I've also met those who do who have poorly behaved, bratty dogs because of it.