Available soon. My cat uses one of their doors. It works.
I built a nice insulated cat shelter a couple years ago for our cats if they end up stuck outside in cold weather.
Last winter a timid little dude started appearing on our doorstep and sleeping in the shelter. We fed him and he slowly over several weeks began trusting us and even coming into the house briefly. I took pictures and advertised a found cat on Kijiji. I got at least twenty replies from the Knights of Righteous Cat Protection and Free Advice instructing me not to bring him to the pound, that the Humane Society would make a fur coat out of him and any home I found for him on the internet was likely a front for someone feeding their dog live cats.
We eventually earned his trust enough to betray it with a couple traumatizing trips to the Vet to lose the jewels and get his shots. We did find a good home, to the great relief of our unimpressed cats, through word of mouth. We even were repaid the vet cost by the new owners. Took a long time but it was worth it.
Indeed it is.
I once picked up a brochure that showed a cute scene on the front, with happy critters–puppy, kitten, even a bee on the wing. The caption read, "There are a few facts of life that you may not know. "
Inside the brochure was a grisly photo of dead, gassed puppies and kittens, with the caption, “60,000 every day.”
A truly heart-wrenching thought. 
So I for one agree: Pets should be fixed.