How horrible. I hate people who do this. Don't get a pet if you won't take care of it!!! A cat isn't a cheap pet. While you can get free kittens and cats all the time (at least there are lots of postings on kijiji with ones available), that doesn't mean it'll be cheap. Fix them! For the love of god have your pet fixed. It makes them happier and more content, and it removes unwanted kittens running around. Not to mention it is good for their health.
When I Was a teenager, my family had discovered that there was a stray cat hanging around. It was friendly as ccould be, kept trying to sneak into the house. He would even purr and offer me snuggles. However our boy would have fought him to the death (you know how cats are). He'd come and he'd go. Eventually, winter time, snow, freezing, brrrrrr! I cried to mom and dad (mostly dad cause he always fell for it), about poor Blacky freezing to death. Well he got to spend the cold months in our shed, it wasn't warm, but it would keep him from freeing, he had food and fresh water. Plus lots of blankets to snuggle in.
Flash forward to either spring or the summer. He made another appearance, he must have been sick, mother took him to the vet, and in the end he was put down. (I was kept out of this, I wouldn't have understood at the time that he was just too sick).
IT makes me HATE people who abandon animals. We had two cats who lived to be 18, they were spoiled, well fed taken to the vet, sometimes too frequently, and well loved. Plus our 16 and a half year old. Each was fixed, well fed, well loved.
Sorta side story. I was visiting my aunt (she's every bit the animal sucker OFL is, she just didn't fix them all), we come across a tiny dog in the middle of traffic. We picked her up, and tried to find her home. She kept going to one house, but the people inside hid. She uhm, appeared either to be pregnant or just had pups recently. Guessing the owners dumped her. We took her to the vet, had her checked out, and she was eventually given to a couple who spoiled her like the child they didn't have.