I don't think that HN, nor the community at large does as much as say twitter or reddit to stifle opposing points of view. Relegating extremist to their own echo-chambers is a good way of proliferating their beliefs. Were their ideas exposed to the world where they would have to defend them, they may be dissuaded from holding such extreme beliefs, or a passerby may see the flaws in their argument.
I wanted to point out it would require radical changes to our current laws and maybe the Constitution. I wasn't sure if he was aware of that. (Stronger versions of this argument, including ones deployed by members of Congress, have said it described current law)
> Were their ideas exposed to the world where they would have to defend them, they may be dissuaded from holding such extreme beliefs, or a passerby may see the flaws in their argument.
This is a popular position in a popular argument, and it's been debated to death better than we can. Here's an summary I found useful https://www.cfr.org/backgrounder/hate-speech-social-media-gl...
One interesting study mentioned in that summation found that temporary internet outages in Germany reduced hate crimes against refugees.
> This paper investigates the link between social media and hate crime. We show that anti-refugee sentiment on Facebook predicts crimes against refugees in otherwise similar municipalities with higher social media usage. To establish causality, we exploit exogenous variation in major Facebook and internet outages, which fully undo the correlation between social media and hate crime. We further find that the effect decreases with distracting news events; increases with user network interactions; and does not hold for posts unrelated to refugees. Our results suggest that social media can act as a propagation mechanism between online messages and violent crime.