I take care of a feral colony along with a couple of friends and have for years. They are all fixed. If a new kitty shows up, a trap gets set up. Sometimes, people don't have the resources or knowledge of how TNR works. If there is a no-kill shelter in your area, they will usually have a TNR program. If there isn't isn't a no kill shelter, then start reaching out to rescues. If your neighbors aren't willing to trap them, the shelter will come and do it, then release them back. If they are reasonable, I understand not everyone is, then a nice conversation about how much money they will save on food plus the health benefits of the cats. Best of luck!