The Founders' idea was that ordinary folks like you and me should be armed just as well as the military (technically, outlawing or taxing fully-automatic weapons is an infringement of the sort they wanted to avoid), so that a tyrannical government, should it arise under a would-be dictator like, say, an Alexandria Occasionally-Crazy, an Eric "Nuke" Swallowell, or a Stacy "I'm the Governor, so there, nyahh" Abrams might be overthrown. The enemies of individual liberty in today's Congress, state legislatures, other bodies, and the media understand this perfectly well, which is why they clamor incessantly to have their intended victims disarmed.

I'll add that any compulsory registration of weapons or demand that potential purchasers humbly beg for government permission to purchase (or privately trade) guns defeats the whole purpose of the Second Amendment—exactly as it is intended to do by corrupt and cowardly politicians, bureaucrats, and police officers who mistakenly believe they own us.