> There is a citizenship aspect of this that seems dubious, though. Expanding "the Golang universe" with a reimplementation

Maybe, but reimplementations can evolve differently... This is why we have forks and distros, and to some extent linux.

> With regards to growing "the authors knowledge" -- contributing to PostgREST would have done a lot more for them there, since Haskell is quite different from Go.

Your making the mighty assumption that one wants to learn a language, or that the language is good (NOT taking a pot shot at haskell here) or that it makes sense in their environment.

I think you raise some important points however, that do need to be part of the decision to undertake reimplmentaion of something that already exists.