One thing that worries me about pet stores is that there is very little incentive for them to be on the lookout for animal torturing sadists. I'm really not sure what the solution is to that.
Hmmm, I don't know. I imagine it's harder to sell an animal with a PTSD-affected personality, so from that perspective, they're incentivized not to harm animals. Did you have something in mind where harming the animal makes it easier to sell?
It's easier to sell animals to people who torture them to death and buy another one like they're a disposable toy. This is a real problem that shelters and breeders deal with.
It's also something people should be aware of when selling or giving away a pet on craigslist.