We have some ideas for new moderation features that we hope will make comment threads more civil. I don't know if they would have helped in this case though.
The one thing that did work here is the flamewar detector. This story dropped off the frontpage extra fast, after which the only people seeing this discussion were people who sought it out.
(Civility isn't even the main problem here - so many of people's comments were superficially civil but callous and misinformed. HN needs empathy, compassion, willingness to listen. It's not impossible to shift culture - Metafilter has improved a lot, but doing that required human effort from its leaders and not just software.)
MetaFilter has several full-time moderators who, because they feel they need to be doing something, are stifling discussion and deleting a lot of threads. Many long-time, valuable members have left the site because of staff decisions.
Meanwhile, a group of noisy, low-value users are mostly allowed to bully others, mock people different than them and even write death threats from time to time.
MetaFilter prides itself on being a place that knows all about Consent™ etc. and maybe that is worth everything else, but it's not a place where people can get together and have a civil discussion.