That's really sad to hear and a pretty awful thing to do. The worst part was that terrible acts like that are totally preventable with proper education about spaying and neutering your pets. It's a responsible thing to do and it prevents tragedies like this from happening by controlling the canine population.
However, that all being said, there will always be the individuals out there who mistreat animals. They're the people who more than likely have some sort of psychological issue or problem and require lashing out or abusing animals to justify themselves. I know that some pounds will require some sort of adoption screening but ultimately they may be futile. I mean, if someone's going to abuse an animal, I don't think it'd be past them to lie on a self-filled survey. I just hope these people are apprehended and punished for this kind of behaviour.