Animal Services and the ACTF are enforcing a law that does not exist when it comes to harassing colony feeders.
"Feral Cat" is not a legal term. In fact, the Dept. of Fish and Game refers to domestic cats as non-game animals, i.e., those that can be killed, as different from wildlife. They talk about free roaming cats as a danger to wildlife, clearly making the distinction.
The California Penal Code only says owners must take care of owned animals, and if feral are considered "owned" then the colony manager must take care of them; i.e., providing food, water, shelter and vet bills.
But, to prove a colony manager is not taking care of cats requires them to access the cat's health, which means trapping them and examining them.
If free roaming, unowned domestic cats are not fed or given water, etc., then, since they are not owned by definition, there is no obligation to provide care.
In any event, when Animal Services or the ACTF goes after a colony or feeder, they are enforcing only their opinion that these cats can be caught and killed or the feeder arrested for violation of CA PC.
Of course if the cats are on the feeder's property, then they are considered owned animals and different rules apply.
But when feeders feed cats in an alley or public property, they are not breaking any law, and neither are the cats considered animals that can be killed or even seized.
Even by the department's own definitions, "feral" or free roaming vats, unowned cats are not considered wildlife, even by their own policy or statistics.
So, if they grab you for feeding alley cats, or tell you to stop feeding on-your-own property cats, they are either breaking the law by enforcing a non-existent law, or telling you to break a CA Penal Code law requiring owners to provide food, shelter and water.