You are spot on.  I worked at HIHS many years ago and the vast majority of the animals put down were feral cats. I used to work with Advocats back then (to try to improve relationships with the animal welfare groups, doesn't seem like they've quite kept up with that) and I was dismayed to see how many people will simply drive out to Old A's or the Kea'au transfer station and dump their cats. I'm now that person who will really ruin a conversation the minute someone brings up how they plan to breed their animals or how their dog just had puppies and now they are giving away un-neutered pups.  I think HIHS could do a lot better (esp at public relations), but I will tell you the problem rests firmly with people who don't spay and neuter.