The logic behind bans on feeding feral cats is that if there is no food available, the cats will go away. This rarely happens.
First, cats are territorial animals who can survive for weeks without food and will not easily or quickly abandon their territory. As they grow hungrier and more desperate, they tend to venture closer to homes and businesses in search of food. Despite the effort to starve them out, the cats will also continue to reproduce, resulting in the deaths of many kittens.
Second, feeding bans are nearly impossible to enforce. A person who is determined to feed the cats will usually succeed without being detected. Repeated experience has shown that people who care about the cats will go to great lengths, risking their homes, jobs and even their liberty to feed starving animals. In addition, there may be more than one feeder and other sources of food, including dumpsters, garbage cans and other animals.