I think it is because most (not all) pro-gun ownership people lean to the right-wing and most (not all) right wingers are into conspiracy theories and think that the government will keep tabs on who owns gun and that those people will be targeted when the government decides to take over (personally, I thought that they already ran the country). These people are also against any sort of national ID system and some go so far as to say that the Twin Towers were crashed into by our own government in order to allow excessive military action (just like some accused the US government of knowinly allowing Pearl Harbor to be attacked) and to allow drakonian laws including national ID cards were samples of our DNA is kept on file. (Because the government is SO intersted in my daily activities that they even installed video cameras on the freeway to see where I am driving to.)

This thread is like a lit match and a spilled gallon of gasoline in the same small room... I give it about 20 minutes to hit.