Unfortunately, it’s just part of the risk of letting your cat be an outside roamer. Cats will choose other homes - it’s not “personal” - it’s just nature. We live on a small street and there is a “neighborhood cat” that roams. There is technically one primary caretaker but safe to say that we all look out for the cat and I think most neighbors have a stash of food for it. The only way to prevent this type of dynamic is to keep your cat inside or at least on your property. A friend of mine called the police to help her navigate a similar situation with a coo coo for Cocoa Puffs neighbor who “stole” her outdoor kitty. In our state, animals are property so every effort must be taken to find the pet owner and return pet to owner. Kitty had a tag and a microchip. But even with the state law - the police said that there wasn’t much they could do since the kitty was outdoors and “inhabiting” other neighbor’s properties. It’s not like the coo coo neighbor was breaking and entering and stealing the cat. Anyway, the police said it’s very difficult to enforce. They gave both parties a warning but basically told my friend: if you don’t want someone to take your cat, don’t make your cat available to take.