the definition of punishment is that it reduces behavior, so any correction that reduces the growling IS punishment. The dog does not know the difference between punishment and correction…they are the same to the dog.
So if Poopsy growls at a house guest who has done nothing you can see to cause it, what kind of owner reaction is appropriate? It seems like just ignoring it so the dog doesnt escalate to biting without warning might lead to the dog thinking the behavior is accepted and it may move on to more aggressive behaviors anyway. Some reaction/correction seems necessary.
So if you are at the bus stop, and you don’t really like the creepy guy next to you but he hasn’t done anything except maybe come a little close, should you be punished for feeling that way? The appropriate way to deal with it is to move away. Same with dogs. Growling is information, it might be a precursor to something more proactive but it might not as well and if you listen and believe your dog, and move the dog to somewhere s/he doesn’t feel the need to vocalize…the dog is more likely to begin to relax. Many animals have a very large comfort bubble. One of my dogs students right now doesn’t even want strangers in her house. It’s frightening for her which leads to lunging/barking and threatening. If I were to have her owners punish that she would not feel better about me, AND she would not trust her owners to handle it. If she can’t trust her owners and she can’t trust strangers, and she can’t stand the social pressure, she is far more likely to take care of it herself by escalating to biting.
That’s why I don’t punish.
Now, that said, you cannot control other people or their dogs and if they don’t manage their dogs well, then you have do to what you have to in order to protect yourself (thinking of the “I was bitten thread”)