The systems on which that person read the false information that drove them to shoot the gun were built by people who read HN. That may sound like a lot of levels of indirection, but to ignore politics for a week seems like a symptom of pretending that we are not a part of the problem.
I think the technology running the web needs to be thought of as a part of the fourth estate. We are not separate from the media which we have restructured.
It is also an experiment. I'd like to emphasize that. It is an experiment. It is OK to not get politics on HN for a week. It will not be the cause of a global meltdown in society.
I'm also pretty confident that if some ground breaking news broke about Donald Trump wanting to launch a nuclear weapon that dang would allow that, but the current noise that is happening can be removed for a week is a good experiment.
But...
The media and technology revolution that we are both living through and shaping with the technologies that we deploy should be something that we actively discuss and wrestle with. I've recently been reading more history of the impact of the printing press (scientific revolution, monarchy => democracy, reformation, and a lot of war).
"This is not a new issue and it is not something that the people who read this site are responsible for."
I could not disagree more strongly. The web is quite new, and we don't understand its impact on society. Certainly the people on this site are not entirely responsible for it, but I think that we should feel some responsibility for it. I certainly do.