While Piazza referes to him as a "gunfighter" that term carries a lot of baggage that is not helpful to the normalization of private citizens bearing arms openly.
That he fought off an attack by using a gun is correct. That he is a "gunfighter" as that term is generally understood is not correct.
A more appropriate term for him would be "victim that survived by using a gun for self defense" - usually shortened to "victim".
Now that we have that out of the way, allow me to thank you for bringing the video back to our attention. The lessons to be learned are invaluable.