It's not that you should "train the growl" out of the dog, it's that you should train/teach your dog that such things are not to be feared.
For example, if the dog growls when a child approaches, then the dog is exhibiting fear, anxiety, etc., over that child. You don't teach the dog not to growl around the child; you teach the dog not to be afraid of that child. As the dog's fear/anxiety is reduced, the growling disappears - however, if something does scare the dog, he can growl a warning.
The growling is a reaction to a situation (in the OP's situation, it appears it was caused due to the manner in which the OP "gave the dog hell"). It's not the growling that is dangerous - it's the fear/anxiety behind the growl and that is what must be resolved.
Most dogs growl if they feel cornered, vulnerable, and in danger. A dog should never have to feel that way. My Bat-dog has a fear of people. I do everything possible to ensure she does not feel that way around people. If she does, I do not reprimand her - I begin working on teaching her that she does not need to be afraid in those situations. At first she was afraid if someone was in her presence - now she if fine with people standing around us. She still gets scared if she feels surrounded by people, so I make sure she has a visible "escape route". Her growling decreases as her progress increases.