Re the question about: "What's the plan, if the govt does something the people don't like, everyone's going to to go down to the white house and twirl their pieces or something?"
Hopefully, no, not every time the government does one crazy thing or another that someone don't like. But it would no doubt be another matter entirely if government acts to end the freedom enjoyed by American people.
And the adoption of the Second Amendment makes a lot of sense considering the fact that the folks who created the government in America over 200 years ago had good reason to fear tyranny, and had good reason to secure the "power" to resist a serious effort to take away their freedom.
Although protecting against tryanny was a big motivation for including the Second Amendment, that amendment did not actually "create" the right to bear arms. It instead limited government's ability to restrict that pre-existing and "ancient" right, a right that had proved its value at other times and places, even England's own past. In its most recent case on the Second Amendment, the US Supreme Court explained that America’s founding generation knew from history, both its own and England's too:
“. . . that the way tyrants had eliminated a militia consisting of all the able-bodied men was not by banning the militia but simply by taking away the people’s arms, enabling a select militia or standing army to suppress political opponents. This is what had occurred in England that prompted codification of the right to have arms in the English Bill of Rights.
"The debate with respect to the right to keep and bear arms, as with other guarantees in the Bill of Rights, was not over whether it was desirable (all agreed that it was) but over whether it needed to be codified in the Constitution. During the 1788 ratification debates, the fear that the federal government would disarm the people in order to impose rule through a standing army or select militia was pervasive in Anti-federalist rhetoric. See, e.g., Letters from The Federal Farmer III (Oct. 10, 1787), in 2 TheComplete Anti-Federalist 234, 242 (H. Storing ed. 1981). John Smilie, for example, worried not only that Congress’s “command of the militia” could be used to create a “select militia,” or to have “no militia at all,” but also, as a separate concern, that “[w]hen a select militia is formed; the people in general may be disarmed.” 2 Documentary History of the Ratification of the Constitution 508–509 (M.Jensen ed. 1976) (hereinafter Documentary Hist.). Federalists responded that because Congress was given no power to abridge the ancient right of individuals to keep and bear arms, such a force could never oppress the people. See, e.g., A Pennsylvanian III (Feb. 20, 1788), in The Origin of the Second Amendment 275, 276 (D. Young ed., 2d ed. 2001) (hereinafter Young); White, To the Citizens of Virginia, Feb. 22, 1788, in id., at 280, 281; A Citizen of America, (Oct. 10, 1787) in id., at 38, 40; Remarks on the Amendments to the federal Constitution, Nov. 7, 1788, in id., at 556. It was understood across the political spectrum that the right helped to secure the ideal of a citizen militia, which might be necessary to oppose an oppressive military force if the constitutional order broke down."
From pages 25-26 of District of Columbia v Heller at:
The Heller opinion is worth reading for anyone wishing to understand the Second Amendment's importance in America, not just for resisting an attempt to impose tyranny but also for personal self-defense . . . and even hunting.