In Spain municipalities are required to feed and care for stray colonies. There are stiff fines for abusing or adopting street cats without municipal approval. There are also potential fines for unauthorized feeding of street cats (though if you want to you can just talk to the muni and get approval). Street cats keep other pests out of neighborhoods. They’re beneficial to everyone - the person those folks want to be pissed at is whoever abandoned an unneutered kitty in the first place.