First of all, the guy that was feeding them probably thought he was doing something good but that is ignorant. That's like those people that feed coyotes and then can't figure out why the coyotes are eating their pets.
Secondly, why does it take something like this for someone to round up a PACK of dogs?
Lastly, if Ingrid (Peta) had her way, all animals would be free, so this would be a common occurrence. Of course, the herds of cats roaming the plains might distract the dogs from eating people.