Unless the site was directly breaking the law, I see this move as troubling. It's almost always better not to drive these kind of people to the underground, and I think most HN readers figure why this is. The problem I see is that in the current political climate the general population won't understand that or is unwilling to.
> It's almost always better not to drive these kind of people to the underground
Seems more like this would remove the echo chamber than drive them underground, I would agree with your point if it was about public shaming. But if FB goes offline I wouldn't consider anyone being "driven underground", more like forced above ground.
The Daily Stormer is pretty radical, but afaik still operates within the law. Taking their platform will put them out of sight and into areas where respecting the law isn't necessary. The enemy you don't know is the enemy you have to fear the most. Unfortunately I feel like most people today are more comfortable with hiding and banning bad ideas than to confront them.