If Hacker News is about the tech industry then we need to see the tech industry clearly, warts and all.
We cannot run away from it. We cannot memory hole it.
HN isn't "about the tech industry" per se - its mandate is to discuss topics of intellectual curiosity. See https://news.ycombinator.com/newsguidelines.html. Celebrity troll moves (or whatever this is) don't fit that bill, so in this case I'm inclined to agree with the users who flagged the story.
In terms of ethics, if the intention is to generate outrage in order to generate views and media coverage, does media coverage help or harm? Research on violence has has reached a fairly strong consensus that symbolism and displaying of cultural values is a major contributor for continued violence and conflicts. What should be the most effective (and ethical) strategy in reducing such display?