That's just collective self defense, though.

Since they (founding fathers) just protected against a tyrannical government, I'm pretty sure they wanted firearms to be fully legal to own in the future to be able to "easily" do the same thing they just did. I just don't think they realized how good the tyranny would get at propaganda and misdirection! They knew and had seen this before, they understood the reason behind it. A well regulated militia- at least to me- meant the organization of people to take a stand against the government (bc at the time there were no military branches). Therefore if the corrupted politicians of the time tried to arrest or stop from being overthrown, the people's militia could work to replace the gov with new individuals!

I honestly think, looking back, the formation of the military (or at least 1 reason) was to protect the gov from its people, but the excuse that it's for foreign threats was used. Outside of a few smaller attacks and WWs, nobody has really "attacked" America in nearly 250 years. Everything else has been self initiated or inflicted; and, personally, I sort of feel the gov keeps all those willing to "fight" tied up in the military, keeping busy fighting other wars so there really is no chance of a domestic uprise.... Obviously all speculation and just presumptions based on actions... I'm no expert!

Edit: at least the last part feels that way. Things are getting really bad at home, so what do we do? Start the first draft in roughly 50 years! Again, not an expert...

I can't speak for every country but that's not the case here. As long as you aren't breaking laws nobody cares if it's meant for defending against home invaders or collecting dust in a collector's storage.