It's worth trying to figure out something as it's a problem here enough people occasionally leave. It's basically mob or follow-the-leader mentality that results in reflexive downvotes on hot-topics when dissenting comments appear. I encountered this when I got into battles with tptacek not knowing he was No 1 or whatever here. I barely care about the popularity or politics as I focus on getting right info to right people. So, I didn't stop when every comment I had was being downvoted at once multiple times. (shrugs)
Nonetheless, I still watched it with fascination in a group dynamics sense as any comment to him had this pattern: a single, nearly-instant downvote (him or biggest fan); a few more in a short period that grayed my post out; his own often going gray after a bit longer; mine ungraying; his ungraying hit and miss; stabilization at anywhere from like -2 to +4. Only happens with fan-favorite people (eg him), tech (eg Rust/C), or topics (eg anti-VC claims naturally) here as my other posts consistently get ignored, a few votes (good or bad), or major upvote for outliers. My net impression was that it represented mob voting by groups for and against those popular individuals as I was unestablished here at the time.
I guess what I'm getting at is there's gotta be an overlap between the spikes, where they're showing up, and who makes them show up. If a negative surge registers as fan-driven pattern, rather than diverse, then points in the other direction might counter it. Some fraction of the total fan-driven votes while ignoring the other votes which were independent. This might stop tyranny of the majority from making dissenting, but otherwise informative, opinions from disappearing. Or it could be as simple as noticing the effect, capping number of negative votes that can come in on that comment/thread, and preventing gray out. Keeps the numbers honest while achieving same objective. So, those are just a few ideas to throw around based on what I've seen.
The data also led me to counter the disinformation spread elsewhere that critiquing these hot people or topics will totally destroy your karma on HN. I've hit them all and consistently to the point that my account would've disappeared within 3-5 business days of beginning. ;) So, the mobs are there & have significant effect that can deter new or less aggressive commenters. Yet, the moderation & community culture keeps it minimal to point that a mix of supportive and neutral, informative comments brings in enough upvotes to easily counter it. Blocking their ability to disappear dissenting comments upon detecting fan-driven, vote surges might be all it takes.