So an Arlington, Massachusetts comic book dealer Travis Corcoran who self identifies as an anarcho-capitalist made a blog post after the Tucson shooting that got a lot of people upset. His blog is now down, but it's enough to say that the post was called "1 down, 534 to go", and he suggested that the tragedy was not the shooting of a Congressional representative, but the collateral injuries to innocent bystanders.
Now, I'm not exactly worlds apart from Corcoran on this one. I posted my own essay in support of political violence. I think political assassination is sometimes necessary. For that matter, if a meteor flattened the Capitol building while the President and VP were giving a speech to the entire assembled Congress, I'd probably just shed a tear for the architecture and the janitors. But dude? Dick thing to say, wrong time to say it, and major, major context fail. Turning reluctantly to carefully considered violence when you honestly believe that no other means will force your government to respect individual liberty? Regrettable, but sometimes better than the alternative. Firing wildly at a representative because you have a bit of a crush on her and don't think she appreciates the gravity of the government's grammar-based mind control program? Different ballgame.
People got pissed off. Bloggers and journalists denounced Corcoran. The Comics Alliance called for a boycott. In short, people in a free society responded as people in a free society should.
And then the police got involved.
Massachusetts is one of the vanishingly few states that requires a permit to own firearms*. And that permit is issued at the discretion of local law enforcement. And can be revoked at any time. You can probably see where this is going.
Corcoran was a dick. But the First Amendment recognizes our fundamental human right to be dicks. There are limits on the expression of that right where violent threats against specific people are involved, but simply approving of an act of violence is not a threat in any legally meaningful way. He was not convicted of any crime. He wasn't arrested for any crime. He hasn't been charged with any crime. You do not get to seize a person's property and deny him a fundamental human right to arms with no conviction, arrest, or even charge. It does not matter how big a dick you think he is. It does not matter how offensive, inflammatory, or frightening you think his opinions are. Suppressing a person's civil rights can only ever be the result of due process, never at the whim of local law enforcement.
This is not the way a free society operates.
[* - Even New Jersey, with all its gun-terror, only has permits to purchase. If you legally come into possession of a gun without a permit (this mostly happens through inheritance or to the folks insane enough to move here from a freer state), you don't need a permission slip to keep it.]