I would guess a dealer is one who does what C.C. Baird, the man we all know and love, does.
I hate to play devils advocate, as I'm sure plenty of animal dealers are like him, but we don't know that to be true. There *could* be dealers who, while they are still involved in collecting animals to sell to animal research, at least treat the dogs better than that. Also...let's not get on the "no animal research" bandwagon. As much as I dislike the idea, as long as it is done as humane as possible, I choke on it knowing that we would basically have to stop advancing in science without animal research. PETA would have you believe otherwise, saying you can use tissues and man-made products to experiment with, but that's just not true.
My A&P instructor was an animal researcher, and while some of the experiments they did are hard to think about (inducing heart attacks to study the effects and study treatment, for example), they were necessary and they treated the animals as well as they could. They were clean, fed, always sedated just as you would a human for surgery, etc. etc. etc.
If I remember correctly, I beleive in Europe animals HAVE to come from breeders if they are going to be used for animal research...which means no shelter dogs and no stolen pets come into the equation. Maybe we should push for that kind of law here? Yes...it means puppy mills will have a better market...but I feel that maybe it beats the alternative...what we say in the C.C. Baird documentary...