Piers Morgan did Larry Pratt the biggest favor anyone in the media could--he made him look like a reasonable person. The favorite characterization the "gun rights" movevment of their opponents is that they are obnoxious name calling liberal idealogues, and Morgan played the villain perfectly.

As the villain, he growled, grimaced, and taunted, yet was unable to respond to "the truth", in the form of Pratt's scripted talking points.
Morgan, like many here, was completely unaware of the the facts, and
so his program was full of sound and fury, but at the end, signified nothing. It actually helped the "gun rights" folks a lot.