Huckabee has every right to say what he said, just as I have the same right to point out that it is wrong, and trades on tragedy to make a point unsupported by the facts. If Huckabee and his followers need a belief in God to recognize that slaughtering innocent children isn't OK, he and they are welcome to that belief, but saying that belief is necessary to act morally and sanely is offensive and wrong. I would point out that the Westboro Baptist Church also claims their beliefs to be informed by God's commandments, as do any number of other vicious demagogues, now and throughout history. One of the reasons the Taliban did so well in Afghanistan was that they railed against the "secular corruption" in Afghani society - does he approve of their solution to that corruption? The Inquisition sought to purge society of its sins by demanding adherence to holy scripture. How'd that work out?
Does our society glorify violence too much? You bet, but not doing so doesn't rely on God. Does Huckabee really believe that only liberals are responsible for creating Halo 2, World of Warcraft, or any one of a dozen first-person shooter-video games, endless Chuck Norris movies, or any of the other violent fantasy outlets commercially available on our stores' shelves? Are all of those things which twist our culture done exclusively by people who don't believe in God?
Huckabee knows better, and since he does, using the slaughter of innocents to sell a Christianist agenda is not only wrong, it's dishonest. Behaving sanely doesn't have to do with belief in God, it has to do with being sane. Adherence to a social contract has nothing to do with belief in God, it has to do with belief in the social contract. I would argue that one part of that contract is dealing honestly with one another and not opportunistically demonizing those we disagree with.