What is wrong with us that we can't do this?

This is off the topic of this blog, but so compelling I had to include it. In the Washington Post, a compelling article on a victim at the VA Tech shooting who is now an advocate for gun control. He is pushing for the simple matter of outlawing the magazines that allow for mass shootings. There is no legitimate use for these things, so why don't we outlaw them? Canada does, according to Michael Moore, so what's wrong with us?