Why is it that while the right to free speech is accepted nation-wide, the right to keep and bear arms is "a matter for local regulation"?

Via the Federalist:

When civil rights advocates on the Left speak of the Bill of Rights, they are generally not referring to all ten amendments. The Ninth and Tenth are frequently forgotten or dismissed as tautologies. The Second Amendment, especially, gets ignored altogether.

This is not just a matter of what legal cases groups like the American Civil Liberties Union will take up. It also trickles down into the general understanding of our rights as Americans.

While rights like free speech, free religion, and the right against self-incrimination are perceived, Left and Right, as the universal rights of all Americans, the right to keep and bear arms is idiosyncratically dismissed as a matter for local determination. That view is increasingly out of step with a nation that believes civil rights should not be different for citizens of different states.

Read more here.