I noticed this a couple of years ago too, I just ignored the letters, continued to receive the emails, and they stopped sending me letters about it /shrug
Heads up, your privacy policy[0] does not work in dark mode - I was going to comment saying it made no sense, then I highlighted the page and more text appeared :)
I did something similar[0] in JS on a Christmas eve eve a while back - needs to run via a server now as Web Workers cannot be loaded from file:// anymore.
The interface also allow to comment, post and interact with the original HN platform. Credentials are stored locally and are never sent to any server, you can check the source code here: https://github.com/GabrielePicco/hacker-news-rich.