[flagged]
"[Yeah, if I'm just gonna be down-voted to oblivion regardless of my participation in the comments, good luck with your 'meaningful discussion'}"
making it impossible for others to read their original comments. If this now becomes a trend I feel like there may be a need to change the rules around editing.
I've restored the penultimate content of each of the posts that they overwrote that way. There remain 5 (including the GP) which just say "Yeah, if I'm just gonna be down-voted [etc.]" but that is because they were posted that way and never actually said anything else—which is a whole other level of abuse in its own right.
I've replied to the user here: https://news.ycombinator.com/item?id=47726912.
I agree that keeping the threads readable is a priority, and if we have to we'll change the rules and/or standard practices. Hopefully we won't have to though.