As written in the decision:

"Because the text of the Amendment should be read in the manner that gives greatest effect to the plain meaning it would have had at the time it was written, the operative clause should be read to “guarantee an individual right to possess and carry weapons in case of confrontation.”  

Or should it have said 

"Because the text of the Amendment should be read in the manner that gave the greatest effect to the plain meaning it would have had at the time it was written to the majority of those with the authority to ratify, the operative clause should be read to “guarantee a people's right to self-govern inclusive of that right to possess and carry weapons within the jurisdiction of that people. And as the people of each jurisdiction have the rights under the tenth amendment (which became enforceable with the 14th amendment) this restriction is not limited to militia uses when due process is followed at each level of the governance.  

As written:

What is more, in all six other provisions of the Constitution that mention “the people,” the term unambiguously refers to all members of the political community, not an unspecified subset. As we said in United States v. Verdugo-Urquidez, 494 U. S. 259, 265 (1990):

“ ‘[T]he people’ seems to have been a term of art employed in select parts of the Constitution… . [Its uses] sugges[t] that ‘the people’ protected by the Fourth Amendment, and by the First and Second Amendments, and to whom rights and powers are reserved in the Ninth and Tenth Amendments, refers to a class of persons who are part of a national community or who have otherwise developed sufficient connection with this country to be considered part of that community.” 

Or should it have said 

“ ‘[T]he people’ seems to have been a term of art employed in select parts of the Constitution… . [Its uses] sugges[t] that ‘the people’ protected by the Fourth Amendment, and by the First and Second Amendments, and to whom rights and powers are reserved in the Ninth and Tenth Amendments, refers to a class of an incorporated body of persons who are part of a national recognized as a legal entity by the community or who have otherwise developed sufficient connection with this country or sovereign state republic  to be considered part of that community.” 

And add:

1. The right to assemble or bear arms is not granted to the ramble even though they are persons in a group. 

2. However, the people's rights do apply to individuals in the Bill of Rights via the common law principle of coverture. 

3. Each of the peoples' obligations to their constituents and to other peoples are intrinsic with these liberties enabled by civilized government.

In republics the rules within each level are substantially the same.  There is a superior, subordinates and peers. The superiors can have superiors. And the subordinates can have subordinates. It's a tree structure.  Chattel owned by the king had more rights than chattel owned by a Duke because the Duke should not offend the King.  A man's home is his castle. Analogous to the principles of coverture, the rights associated with residences vary with who owns the home.  When a city has legal jurisdiction, the defense of its citizens is the city's responsibility and obligation.  The citizens owe an allegiance to the city which they demonstrate by good conduct.  Then the city extends its rights to residence that the civil government allocates. The city has the responsibility to defend its citizenry, and its strategy might be to have a militia.  The second amendment is a guarantee that the federal government will not take away the city's right to have an armed militia.  It also guarantees that a city could determine what arms were not allowed to be ready for use within their jurisdiction.  The word "infringe" prevents a change. It does not dictate that a strategy where persons must be allowed to plan for homicide (if needed) as their defense.  

Can there be a single rule dictated? 

Guns don't kill people without someone pulling the trigger. But it's also true that bullets do not stop bullets in midair.  The entire concept of homicide reciprocity as a defensive strategy breaks down when no matter which way you look, someone is there you don't know.  And if there is a criminal, someone is too close behind them to be sure it will be the correct homicide.  Situations are too varied for a simple one size fits all answer.  The "best" answer on a colonial plantation was different than the one on the edge of armed angry hostile territory than the one in the Amish community.  The question needs to be, "Who and with what criteria should the rules (plural) be made?"   The answer was, "the people" who had formed a society. 

Is this what was ratified?

It was much easier to see at the time of ratification that a single all in decision from the federal government could not get the votes to be ratified. Therefore, there cannot be individual rights for manufactured arms for constituents of the rabble. Instead, a person must be a constituent of a responsible and accountable legal group of persons subordinate to the appropriate governmental jurisdictions. This legal group, called the people (its identity is based on its function not its geography), can use its rights to franchise the needs of its constituents.