And the 2nd protects thr right to keep and bear arms because sometimes, individually or collectively, people have a need to kill other people.
What better for this than a weapon specifically designed to do so?
What circumstance would require an individual to own an anti-tank rocket launcher?
How about a .50 cal fully automatic machine gun?
Even Heller, as I understand it, acknowledges the government's right to regulate (within constraints set by Heller, and elsewhere).
In case you raise the DICTA argument; as I understand it, it is important to note that dicta are not binding precedent, so comments made by Justice Scalia in dicta do not establish the law in the same way that the Court's holding does.
However, is it not true that, In the case of of Heller, Justice Scalia wrote in dicta that "Like most rights, the Second Amendment right is not unlimited? Which is to say, It is not a right to keep and carry any weapon whatsoever in any manner whatsoever and for whatever purpose." He went on to explain that the government has the authority to regulate certain types of weapons, such as those that are "dangerous and unusual."
The important thing is, that although this statement by Justice Scalia does not create a binding precedent, it is significant because it reflects the opinion of a Supreme Court justice and
may be considered persuasive authority in future cases. However, it is up to future courts to determine the scope and extent of the government's authority to regulate arms.