"Second Amendment's protections...do not extend to the District of Columbia because it is not a state."
By her logic then the Amendment (I forget the number) that provides for an income tax should also not apply to the District of Columbia because it is not a State. Oh joy, oh joy, DC residents should demand to get all the federal taxes they have paid over the years returned. Now they no longer have to be one of the highest taxed jurisdictions in the country!!!
Nope. The 2nd Amendment was a declaratory restriction on federal powers, the 16th Amendment extended federal powers.