That's very nice.
Now, do you treat your fellow humans like dogs? Is the social standing between you and dogs the same as that between you and human minorities? Can a Rottweiler or Pit Bull read those depictions of Hell Hounds, look you in the eye and say, "Hey, that's how they used to (and in some places still do) talk about me...."
If not, maybe the analogy isn't all that strong. If yes, well, that's another situation entirely, and not only because you have a talking dog.
If you want to test if you really can do this, reskin your orcs to carry resemblance to, say, poor, rural Caucasians from Appalachia. Publish it, and see what you get. After all, orcs are fictional, so nobody should get their nether garments in a twist over how they are depicted, right?