Typical liberal labeling used to distract from the real issue and portray the opposition as something to be scorned or not worthy of serious debate.
Ever notice how there is a universal image of "gun nuts" present among leftist comics and writers? Fat dumb looking redneck, NRA hat or shirt, shitty camp, AR style rifle, it's a very common image. This is not an accident. It is intended to be used to immediately put anyone defending gun rights on the defensive, and to ensure the debate is controlled by the leftist. The opposition has to defend themselves and overcome the mental image of gun owners as stupid rednecks and gun control advocates as enlightened and intelligent civilized people talking down to these crude hicks. "Gun nut" is among the long list of labels the left uses to control debate and steer it in a way that avoids certain obvious truths.
The left portrays the gun problem in America as a gun nut problem. As if removing these rifles from the hands of NRA rednecks is the solution to a problem. In reality, gun violence in the US is not an issue about rednecks at all. Or even white people.
5% of the population commits more than half of all murders by firearm. 70+ percent of these murderers are already felons. Both the victims and shooters in this segment are black males 15-29. 95+ percent of these murders are committed with handguns.
Overall, AR style semi automatic rifles account for a negligible numbers of deaths per year. These guns are expensive, hard to steal, and hard to conceal.
The amount of violent crimes committed by fat white redneck members of the NRA using semi auto rifles is so small there is not a good statistic for it.
The US has a young black male with handguns problem. That's it. If you remove the murders committed by this group, the US shares gun violence stats with countries such as Finland. Hence the "gun nut". A liberal would sooner die than confront the reality of gun crime. Hence "gun nut"