Grossman is more of a summarizer and speaker.
For example, he gets criticized for his suggestion that violent video games prime aggression. There is a tremendous literature on that with complex models of aggression being multicausal. His view though comes across as simplistic.
There are more sophisticated views of the inhibition to fighting that Grossman talks about from the Marshall work.
But then, you have to go read the PhD writtern crappola - which I get paid to do!
Dave Kenik in Handguns had a good couple of articles on being a hero. He was an NTI participant when I was there. I think the resolution is using common sense in choosing an action as compared to what we view as nonthoughtful posturing.
The initiation of the gun fight question is one for thought rather than blanket pronouncements. The Internet tends to generate the latter - it's a group polarization effect, sometimes.