Because Rust is an excellent language that pushes you into the "pit of success", and consequently software written in Rust tends to be fast, robust and easy to deploy.
There's no big mystery. No conspiracy or organised evangelism. Rust is just really good.
Worth noting that “robust” and “correct” are orthogonal. Graph databases (well, any database) seem like an area where correctness particularly matters, and I doubt Rust gives any meaningful advantage there.
They absolutely are not orthogonal. They are closely related. In any case, Rust improves both.
> I doubt Rust gives any meaningful advantage there.
Advantage over what? Haskell & OCaml? Maybe not. C++ or Python? Absolutely. Its type system is far stronger than those, and its APIs are much better designed and harder to misuse.
(Which may not all be true, but perhaps moreso than your average project)