Possibly:
1. Piggybacking established brand names (Postgres + Rust)
2. … without practicality nor advancement (e.g. this solves no extra problems)
3. … without trust (i.e. LLM-driven rewrite, with no capabilities to thoroughly review it)
I think people get easily upset when the title has high-signal names like Postgres, and the title touts it somehow, yet it’s obviously impractical for obvious reasons (short-/long-term practicality, social trust & network effect, etc)
Yeah, if the title was : Vibe coded SQL engine written in rust, I don't think much anger would be found in the comments.
But then its credibility would be abysmally low, which makes it undesirable for the authors.