Comment by Pfeil

You never have only one requirement to satisfy. For example, if you'd welcome a certain amount of contributors, your language should be something people know or people like to learn. And of course it may just be the mood of the initiator, which I find completely fine.

Personally I find rust projects very inviting. Figuring out the amount of unsafe code is easy with grep/rg (to a certain degree), the project structure is pretty standardized, etc. All of this makes even a complex project relatively easy to start with. At the same time, the language is pretty usual (C-like and readable). I understand people like it, and writing "written in rust" is a good call for those people, I guess.

"Written in JS" would communicate something else than "written in D" or "written in C++". It communicates a lot of things implicitly.