It's probably because of HN's anti-LLM filter. I don't know if submitters use LLMs to touch up their descriptions or if these descriptions often use LLM-like phrasing.
Also lots of "genuinely" and some air quoted phrases which are another tell.
I guess you folks are right and it's probably the llm filter. I looked at the GitHub and thought it had too many screenshots to not have had some human effort, but who knows these days.
If that's what happened, I wonder if the same filters exist for tools like Grammarly. Some people are English as a second language, and some people simply want to put the best foot forward and make the best first impression.