Finally you partially answered the question, amazing!! Now for the for the rest of it, your interpretation. Is your view based on the modern concept that only includes what you have posted or the Original Intent of the founding fathers based on their concept of militia AND their writings clearly defining what they meant when they included the militia clause AND the shall not be infringed determination?
Ok. since I am on the liberal left and a patriot to the federal Cause; here it is in a nutshell,
A well regulated militia, being necessary to the security of a free State, the right of the People to keep and bear arms shall not be infringed.
There is no appeal to ignorance of the Intent and Purpose of any law, much less a supreme law of the land which declares what is necessary (and proper) to the security of a free State.
10USC311 defines the Militia of the United States.
Not All of the Militia of the United States is well regulated enough to be organized.
Only well regulated militias of the United States are necessary to the security of the several United States, should their be Any need to quibble, regardless of any (Southern) Cause.