It seems their point is that the percentages are similar to success, so although the subject is different, the comparison still stands.
I'm sure people have been "the good guy with a gun" a number of times, but the chance of success and the risk of shooting an innocent factor into the continued use of that as an argument point against gun control.
(Edited: they're to their)
People will believe what they want to believe when it comes to gun control. I think the article itself does a pretty good job with parody alone to make it's point. The "red wire" comment was also a decent comedic analogy of what the argument for a "good guy with a gun" is.
If you don't see their intended point already, then I don't think I can explain it in any way that will help.