Here in the Hamptons, ARF is very present. There are feeding groups that go around to the feral colonies and lovingly feed the animals. Pets are trapped-spayed/neutered-vaccinated and released back to the colony. One ear is lopped partially off so ARF can tell that the animal has been taken care of. One of the houses we lived in this past spring had a colony living behind of about 12 cats - a rather small one. We got 9 trapped and only one had to be put to sleep, she ended up having a huge tumor in her stomach, she wasn't just chubby like we thought. My girls had named her Lucky because in all the times we had been feeding them, she was obviously very old, beautiful long fur (though matted), and missing most of her teeth.
We put a combo of hard/soft food out 2x a day for the colony on our back porch - some would come up while we were there, but we could only pet a few of them until they realized we were touching them.
Always water, and once a day we'd heat some milk for all of them, as a little treat.
One cat was all black, small, missing an eye that was severely infected, and very pregnant. ARF kept her til the babies were born, adopted out all 5 of her babies, and released her back to our house. Gypsy - as I called her was so vicious with them so the girls and I went in a few times to visit, she would be nice and calm each time we were there to talk to her.
There was one kitten in the colony, about 4 months old. She was trapped, spayed and chipped. A wild little thing my youngest daughter named Pipsy - she was Gypsy's only surviving baby from her last litter. We brought her into our house and it took about a week before she would come out from the little cave area we made for her, but now she's SO affectionate, we know she's very thankful for her little comfy life now. She's so affectionate that sometimes I have to keep putting her to the side off of me and eventually she'll settle down next to one of our legs, or across our lap - and just stare at us, it's so cute.
Anyway, all that rambling to say that there are so many pet lovers, and way too many animal haters - if they don't want the animal or can't take care of it, then drop it off in a box at a vets door during the night, or some animal shelter, or at someones house that they know has a well loved animal and let them deal with finding a good home for the pet. How hard can that be? And as much as I am against animal cruelty, I still feel that if an animal has killed another, it will continue. I feel they have to be put to sleep because the consequences of keeping that animal alive and the damage that will be done is not good. Regardless of how much the animal is tame and loving when around their owner, you can't predict what is going on in the animals mind and what they will do. Control has to be with not only keeping a leash on the animal, that only goes so far in protecting other animals and people from them.