The government is authoritarian and commonly hostile to much of the population. Many people who advocate keeping guns have fear of the government in the back of their minds. But that's a crazy response to a real problem. In fact, the corporations set the conditions within which the government operates, and control it to a large extent. The picture presented in the media is constant, day after day.
People simply have no awareness of the system of power under which they're suffering.
People have all kinds of motivations for opposing gun control, but there's definitely a sector of the population that considers itself threatened by big forces, ranging from the Federal Reserve to the Council on Foreign Relations to big government to who knows what, and they're calling for guns to protect themselves. I look around and see a lot of Third World countries where, if the citizens had weapons, they wouldn't have the government they've got. I think that maybe people are being a little shortsighted in arguing for gun control and at the same time realizing that the government they've got is not exactly a benign one. Your point illustrates exactly what I think is a major fallacy. On the other hand, it's at least partially accountable, and it can become as benign as we make it.