No doubt you don't have a clue of what you're talking about. Aggression is natural in dogs but can be trained out of them, and this dog is proven aggressive.
When a dog comes from accross the yard snarling it is not wondering if you are human, it is exhibiting dominance or defending it's turf.
pretending that a lab is incapable of being aggressive is like pretending a lad is incapable of being a dog.