While I'm not quite as on board with this snatching assault weapons as some others are, that well regulated militia clause was more expected to keep the state secure from external threats rather than internal despotism. While the English Bill of Rights of 1689 of which the Second Amendment drew its influence from, did explicitly secure the right to be free from forceful disarmament by the state, the Founding Father's intended the checks and balances of the Federal Republic to keep domestic tyranny at bay, not the arming of its citizens. Mob rule scared the sh**t out of them, they didn't want the masses deciding to burn the system down willy-nilly because of some perceived repression.
Once we attained an organized military, there was no longer a need for a well-regulated militia. I'm all in favor of people wanting to arm themselves, and I'm even willing to grant them their right to be paranoid of government repression. But this whole self-aggrandizing narrative of patriotic duty by excessive self-armament is bogus.
This is pretty accurate, except for the last part. There was a lot of concern during the founding about a standing army. You can read plenty of skeptical quotes in the recorded debates on ratifying the Constitution. That's why the constitution limits military appropriations to 2 years, and its why Congress's power to create an army is optional rather than mandatory. Although we know Congress realistically won't stop having a military, it is possible. In a future where we no longer had an army, the concept of militia would be useful again.