I don't think anyone here, or the police for that matter, or anyone else who knows up from down, thinks that this was really an "attack" in terms of aggression. It was either play that got out of control (with a very inexperiened animal) or the act of a despirate creature that might have been starving or high on drugs itself.
That said, I'm glad your labs are great. Most labs are great. But I've met some VERY mean labs in my life. How they got that way, I don't know, but they were just plain scary, made more so by their owner's belief that "oh, he's a lab, he won't hurt anyone." Labs are great dogs, and most of them very, very gentle and sweet (if rambunctous). But no breed is immune to aggression under the right circumstances, including poor breeding and poor training. However, labs should not be vilified by this incident, any more than any breed should be.
However, this is NOT about breed. That puppy was too young for breed to play any role in it except for strength and size. This is a case of human neglect and negligence, not a "vicious dog."