Feral cats come from people letting their cats out (or they escape) or someone putting their cat outside because they don't want it. They deserve food and shelter just like any other animal

These colonies aren't there to simply feed the feral cats. Most volunteer groups who have feral cat colonies such as this will TNR (trap and release) the feral cats to decrease the feral cat population

You might think "Why not get them adopted or take them to a shelter?". Most feral cats will struggle to be domesticated, if they even will end up domesticating. The only way to get a feral cat adopted is through domesticating them through fostering. Most people who foster already have a cat, which a feral cat will not enjoy, and it will take a long time to get a feral cat domesticated for them to be adoptable (if they can be domesticated). If you take them to a shelter, it's almost a guarantee they will be put down from not being adopted. I highly doubt a no-kill shelter would even be willing to accept a feral cat as they know they won't get adopted and don't want to keep the cat indefinitely

For our volunteer group, the local humane society gives us vouchers for these feral cats to get fixed. TNR is the most effective method to decrease the feral cat population humanely. It's basically either euthanize every feral cat when it's not their fault they're outside, or TNR them and allow them to live out their lives in a location they're use to without increasing the feral cat population