This is a matter not of tone but of content, and the toxic effects of such content. If only we could rely on well-reasoned user responses to neutralize those effects. But internet forums don't work that way, nor large groups of humans in general. For HN to have civil, substantive discussion, moderation is sadly necessary.

Detaching comments, with an explanation of why, has proven to be one of the best moderation techniques we've tried. The sort of rant we're talking about isn't primarily about the topic at hand—it's primarily about state-changing the conversation to something agitated and ragey. Because that counteracts the purpose of this site, such posts forfeit their right to an ordinary position on the page.

Those who want to read such comments still can, but you literally have to go lower to do so. That seems fitting to me, and a reasonable balance of concerns.