You'd be surprised to find how many liberals believe this...and why wouldn't they? It's what liberal teachers are teaching our children in public schools. I'll bet you this quote never comes up:
Don't get me wrong, personal security makes the Right to Bear Arms further necessary. While major cities and even smaller towns had some law enforcement, just like today the sheriff couldn't stop a robbery at the sight unless he happened to be on site at the time. Despite what liberals in their Happy Imagination Hats believe, you can't call the police if someone is trying to assault you, at least in most cases.
However, the reason for the Second Amendment, was, is and always will be is to ensure that the citizens of the United States are capable of remove our government if the government ever becomes tyrannical.
(I AM NOT suggesting that such a revolt is currently necessary, nor should this post be construed as a call for such a revolution. Anyone who takes this post to mean we should revolt is wrong.)
It turns out the Founding Fathers wanted to ensure that our nation could stand up against our own government if it was ever necessary. So far, in the over 230 years of this nation's history, such a revolution has not been necessary -- but only a fool would assume that it is 100% impossible for such a need to arise in the future.
Therefore, if the United States government has a particular firearm, citizens DO in fact "need" to be able to purchase the same firearms, just in case we need to remove a future tyrannical government. Whether we would need an M16 rifle for hunting deer or bear is irrelevant. We would need that if we ever needed to overthrow a tyrannical government (which would absolutely have those weapons, because duh).
Liberals have either missed the point of the Second Amendment or are willfully ignoring it. The Second Amendment is about protection from tyranny from within. Plain and simple.