Just how many of the users here are in a well-regulated militia? And show of hands? None? I thought so.
Sorry, but the second amendment is a relic from the American Revolution and the Federalist vs. Antifederalist era of American political culture, nothing more - The Second Amendment in its original context was a direct reaction to imperialist aggression from Great Britain, and also a way to protect 'state rights' as people of that line of thinking feared a standing federal army and sought a way to arm state-sponsored militias, what would now be our National Guard/Reserves in case of defense from the big bad evil federalists.
Any modern interpretation deviating from that is simply the result of successful lobbying and misrepresenting of facts from the whack jobs at the NRA, in particular.