So, if I'm to accept your premise that the 2nd applies to citizens of other countries, then the entire Constitution must as well and we better get busy overthrowing dictators.
But then, I don't happen to think that the 2nd, or any of the Constitution, applies to anyone beyond our borders.
And our courts seem to think that way too.
However, it does apply to me, and we need to get busy overturning 70 years of un-Constitutional gun laws.
No - that is not a logical progression. If it applied to other citizens our government could not infringe upon it. The governing contract involves the US Government as the governing power. It restricts the US government - but under no reading could one ever say it requires the US government to go around the world enforcing those rights. It just limits the US government's powers.
Though how is the Constitution phrased on the requirement of republican form of government?