Sorry I was not able to attend sooner.
P1: all people have a right to keep and bear arms.
P2: Individuals not related to the Militia are People.
C1: Individuals not related to the Militia have a right to keep and Bear arms.
P3: All Individuals have a right to keep and bear arms.
P4: The Federal government is restricted from infringing on the people's rights to keep and bear arms.
P5: Limiting the purpose of keeping and bearing arms is an infringement.
C2: The Federal government is restricted from limiting the purpose of the people's right to keep and bear arms.
The constitution does not limit the rights of the people. The constitution outlines the powers of the federal government. You would have us read the constitution as a limit on people's rights. Trying to assert that the contemplation of right to keep and bear arms was in no way connected to the right of self defense. Yet we see Blackstone commenting on the English parallel saying
"The fifth and last auxiliary right of the subject, that I shall at present mention, is that of having arms for their defence, suitable to their condition and degree, and such as are allowed by law. Which is also declared by the same statute I W. & M. st. 2. c. 2. and is indeed a public allowance, under due restrictions, of the natural right of resistance and self-preservation, when the sanctions of society and laws are found insufficient to restrain the violence of oppression."
In fact, we see the concept of self defense occurring in all of the philosophical writers which we recognize as having ample influence on the founding fathers. These authors include: Hobbes, Locke, Milton, Montesquieu, and Rousseau. It honestly seems absurd to imagine that the drafters recognized an unalienable right to self defense yet imagined that weapons would stay inaccessible save for threats to the common defense.
Nevermind that early courts recognized the second amendment as an individual right. Nevermind that early courts looked to Blackstone in their interpretation, and Nevermind that the consequence for reading the 2nd Amendment as you do potentially eliminates the entirety of the second amendment.
You comment that a reading of the second amendment that recognizes an individual right makes the prefatory clause superfluous, but do not stop to recognize that a collective right makes the entire second amendment superfluous. On what grounds could any individual make a claim regarding the violation of a second amendment, if we read this as a collectivist right?