[alethiophile]

...The pro-gun crowd are the ones who constantly quote the amendment verbatim. They don't "hate" it.

And yes, it doesn't explicitly say in the text of the amendment what kinds of threats the militia is meant to defend "the security of a free state" from. This is why you need to make obvious deductions based on context. There's certainly no basis, either in the literal text or in contextual deduction, for the idea that the founders only meant it as security against foreign invasion.