You have folks with anger & desperation as part of their mental core, with the added motivation to hurt others, for whatever reason, be it robbery, rape, hatred, etc.. These are the folks that will use whatever tool they can obtain to hurt whoever it is they want to hurt. Frequently that's a firearm, because, it can be done at a distance. But other items can be used as well. These are the folks who will shoot people in the back of the head, if they could, and would be xo's "bad gun nuts"
However, notice that even good gun nuts are demeaned. They apparently piss & moan.....not sure about what, but according to the professor, that's a good gun nut. Notice how completely different the 2 types of "nuts" are. One that wants to inflict hurt onto others, the other law abiding "moaners"
But, it doesn't stop there....apparently there's the "useless gun nut", who's primary critique, is they're not omnipresent, and able to be in every place, where a bad gun nut is inflicting carnage. Not sure how that makes them useless, since the parameters here is coincidence, which no one has control over. Good & Useless gun nuts don't go looking for the bad ones. That's not and has never been their function. Good & Useless gun nut have no mindset that they can stop all evil acts, or prevent all manners of killing. They are simply an added level of potential protection, that otherwise would not be there
And yet, notice how often gun nuts are used in general, as a negative, with the inferrence that they're all bad in some way. That's why the question was posed to differentiate gun nuts from its general use by the good professor. Since, without it, he continues to use the generic paint brush of "gun nuts", lumping the perfectly responsible legal gun owner with the one that's perfectly willign to shoot someone in the back of the head. Not very rational now, is it