We took Show HN off the title because this post wasn't a valid Show HN—in fact it made a point of
not being tryable by the reader. See
https://news.ycombinator.com/showhn.html. In that sense, yes, you broke a rule. But not otherwise.
We downweighted the thread because ChatGPT is the supernova of the moment, exploding and filling every corner of HN. In such cases, we downweight most follow-up posts. We're trying to find a middle ground that leaves room for significant new information without being so extreme that the site is completely dominated by a single theme. One sign that the needle is in the red is when the site starts to break out with immune reactions like https://news.ycombinator.com/item?id=33880024 (see also https://news.ycombinator.com/item?id=33888500 in that thread).
The test for whether a post is a follow-up vs. a fresh story is: can it support a substantively different thread than previous threads in the same sequence? Looking through the comments of this one, it's clear that the answer is no: they are almost all (maybe even 100%) generic and could appear in any place with the word "ChatGPT" nearby. That's not your fault, but it's moderation's responsibility to look out for the global state. I know it sucks when it's your post that gets optimized down for this reason but if you consider the core principles that we're optimizing for intellectual curiosity [1] and curiosity withers under repetition [2], it should be clear why we don't have much choice.
[1] https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...
[2] https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so...