I disagree with the sibling comments about defending the country against an invader (if your country is facing invasion, weapons will be readily available) and defending yourself against crime (it's a non-issue in any non-failed state, and in a failed state weapons are readily available anyway and rarely make any difference).
But in a world where wealth inequality is increasing, where surveillance is ever more present, the tiny probability of the population being able to resist when it finally rises up justifies the very tangible downsides of an armed population.
I am aware that there are many arguments against this view, but I think the downsides of an authoritarian state with a monopoly on violence are too dire to be brushed aside.