I never said that the gun CAUSES the ND. But face it. Even well-trained people could be a little more likely to have a negligent discharge with a certain make of gun than with another make of gun. So a certain make of gun might LEND itself to being somewhat less safe even in the hands of a well-trained person. And when an ND happens, as did today, we might make a good guess which gun it was.
A defender of that make of gun might give all sorts of excuses (more of that particular gun in people's hands so more chance of an ND, or people need to be better trained, and so on). But when the ND happens more often with one gun than another, it's stupid not to think about fixing more than just the people involved.