Is there any reasonable argument that the second amendment is actually a good thing?

[Recursion]

172. Yes: we're an incredibly violent country, which is why people have guns

You're confusing the cause and the effect. We are and have always been a much more violent country than most countries in Europe. We're much more comparable to the other revolutionary republics in the hemisphere than to the European social democracies: Mexico, El Salvador, Venezuela, Guatemala, Colombia, Mexico, Brazil, Ecuador, Nicaragua, Paraguay, and Cuba all have higher murder rates than the US. Read that again. You probably won't believe it, so I invite you to look at the list:

http://en.wikipedia.org/wiki/List_of_countries_by_intentional_homicide_rate

Those are our peers. Those are the countries we are like: western hemisphere revolutionary democracies with a history of slavery, high inequality, and diverse populations (all three of those are tied in to each other).

Unlike most of those countries (again, all of whom have a higher murder rate than the US), we have guaranteed our citizens a right to arm themselves in defense against that violence.

EDIT: at first I stupidly had typed "Canada", which does not have a higher murder rate than us and is not a revolutionary democracy with a history of slavery, and also does not have as strong gun laws as, say, Mexico or Brazil.