An interesting example of both LLMs' strengths and weaknesses. It is strong because you wrote a useful tool in a few minutes. It is weak because this tool is strongly coupled to the problem: filtering HN. It's an example of the more general problem of people wanting to control what they see. This has existed at least since the classic usenet "killfiles", but is an area that, I believe, has been ripe for a comprehensive local solution for some time.
OTOH, narrow solutions validate the broader solution, especially if there are a lot of them. Although in that case you invite a ton of "momentum" issues with ingrained user bases (and heated advocacy), hopelessly incompatible data models and/or UX models, and so on. It's an interesting world (in the Chinese curse sense) where such tools can be trivially created. It's not clear to me that fitness selection will work to clean up the landscape once it's made.