They seem to ignore that the second amendment creates a well-regulated militia of citizen soldiers. We call that the National Guard.
Article 1, Section 8, Clause 16 gave the power over the militia to Congress, and they've used that power 5 times in Militia Acts to "organize, arm and discipline" the militia. The Second Amendment can neither protect the arms of the militia or protect any right to bear arms in a militia.
The militia is "well regulated" in 10 USC 246 under the powers granted to Congress in Article 1, Section 8, Clause 16.
U.S. Code § 246.Militia: composition and classes
(a)The militia of the United States consists of all able-bodied males at least 17 years of age and, except as provided in section 313 of title 32, under 45 years of age who are, or who have made a declaration of intention to become, citizens of the United States and of female citizens of the United States who are members of the National Guard.
(b)The classes of the militia are—
(1)the organized militia, which consists of the National Guard and the Naval Militia; and
(2)the unorganized militia, which consists of the members of the militia who are not members of the National Guard or the Naval Militia.
The Second Amendment can only limit the power of government, not expand it. That limitation was expressed in the clause "the right of the People to keep and bear arms shall not be infringed".
Nothing in the Bill of Rights limits the rights of the people.
The framers were opposed to the standing army that we have no because of the many problems that it creates, most of those problems we now refer to as the Military Industrial complex. They supported the idea of citizen-soldiers that were overseen by a well-trained professional officer corps that they would create at West Point. The current situation of violent public yahoos with guns is definitely now what they had in mind in 1783.
They funded a standing army from 1776 to current day. Congress reorganized the small standing army post-Revolutionary War into the Legion of the United States in 1792, the very same year that they passed the first two Militia Acts. If they were opposed to a standing army, they went about it in a strange way.
A recent federal court ruling appeared to expand Second Amendment rights to private citizen militias, which a historian of early America explains is not what the founders intended.
theconversation.com
Given that Congress can disarm the militia, or refuse to let any serve in the militia, the militia isn't protected by the Second Amendment at all.