I don't think that it's any more Furry Confusion for a mouse or any other animal to have a pet dog than it is for a human to have a pet dog. I just think that it's Furry Confusion for any animal to have a member of its own species as a pet.
It's usually established in that situation that dogs would be furries too.
But aren't the "anthro" ones Dogfaces, while the "non-anthro" ones are just dogs.
So this settles not so much on the mere stance and that animals assume (bipedal, quadrupedal, or otherwise) as it does on how the animals are treated in the work. If a two-legged animal and a non-bipedal-stance-capable four-legged animal are treated on par with each other, then there is very little or hardly any Furry Confusion unless the two animals are of the same species.
Why is there no confusion when you see a human next to a chimpanzee? Superficially, we and chimps are fairly similar. The major differences are our bipedal locomotion, our smaller jaws (which still have a similar face structure to that of chimps) and our larger brains. Surely the same could be the case with Goofy and Pluto? One offshoot of their evolutionary tree gained a bigger brain, opposable thumbs, and a larger brain, while the other offshoot remained in its wolf-like state. Goofy is still unlikely to treat Pluto as an actual person, just like we are unlikely to treat a chimp as one (except in anthropological studies and old Ronald Reagan movies).
Because humans are from a different genus from chimps. Goofy and Pluto are both labelled as dogs.