Off topic: lately, I've noticed a lot of dead HN comments and entire shadowbanned accounts that seem totally reasonable and on-topic. I really wish there was a way to flag dead comments that were auto-flagged as false positives, because in the past HN mods have said people who comment from IPs that were previously banned also get shadowbanned.
Next time, take a look into their comment history. A lot of hellbanned people are totally reasonable on some topics but have pet topics about which they can be incredibly obnoxious.