Slippery slopes and the 2nd Ammendment

YESTERDAY on "Fox News Sunday", Antonin Scalia, the Supreme Court justice, suggested that Americans may have a constitutional right to own and carry shoulder-mounted anti-aircraft missiles.

Full story: http://www.economist.com/blogs/democracyinamerica/2012/07/gun-right...

Okay, this is absurd. Seriously, how can people really defend the second amendment to the fullest extent if it's going to permit absurdities like this.

The fact is, the more guns you have within a country, the more danger you have. Whether you have them there illegally, or legally, more guns represent more danger. More potential to harm, more possible danger. It's exactly the same basic logic that stops us from wanting nuclear proliferation.

So how do people defend the second amendment, in the light of events like this? Plus I believe the full text of it is

"In keeping with the mainatence of a well regulated militia, the existence of which is necessary for the protection of the freedom of these United States, the right of the people to bear arms shall not be infringed"

People are aware, are they not, that the right only exists in so far as it maintains the existence of a "well regulated militia". As far as I can see, allowing just anyone to have a gun isn't the same thing.