It’s a thought experiment for how mathematicians could have assumed the continuum hypothesis, and how dangerously close they came to making that mistake. It’s not an argument in favor of CH.
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.