Perhaps that is done to avoid the rate limiter?
I can usually only make five posts in one 8-hour span, and then the sixth attempt says, "You're posting too fast. Please slow down. Thanks. Also, don't count the number of posts tptacek can make in one thread in one hour and compare it to your total for the entire week, or it might raise your blood pressure."
I am barred from having more than half a conversation in one day, while it seems that [some] others can post as often as they can hit "[reply]". So yes, I do feel censored on HN. The article didn't even mention the post-rate limits.
Also since you mentioned a particular user your comment will be removed. Funny how that works.
I can recall at least one instance where he replied to me directly, and I wanted to engage, but couldn't, because I was "posting too fast".
It's the network neutrality issue writ small. Some people have fast lanes on this site, and others have slow lanes. I don't like it here, and it annoys me when I notice it. If it becomes the status quo for the whole network, you can be sure that I will be engaging in "shovel vigilantism" in the dark of some nights. Freedoms of speech and publication are no longer supportive of liberty and equality when certain favored people are allocated 10000 times as much speech as most other people are usually allowed, and drown out all other voices with their sheer volume rather than the merit of their claims.
Have you considered, perhaps, changing your behavior?
If you're concerned about a specific IP, and haven't been abusing HN, it should be easy to clear up by emailing hn@ycombinator.com. And even if you have been abusing HN, we're always happy to unban people (and/or their IPs) if they give us reason to believe that they've taken https://news.ycombinator.com/newsguidelines.html to heart and will follow the rules in the future.
Edit to add: Without more details from you, I can imagine the mods being hamstrung with respect to figuring out or explaining what's going with what you're observing. Likewise, there's nothing preventing you from continuing your comments here while also emailing them. Particularly as it seems you'd like to continue to participate on HN. I can imagine you'd prefer to do so without the hassle you're currently experiencing.