Fuchsia Programming Language Policy (fuchsia.googlesource.com)

As a Go programmer, it doesn't really seem that notable or surprising to me that Go isn't considered the best language to use for implementing an operating system.

Already a big discussion about that here:

https://news.ycombinator.com/item?id=22409838

Decisions are entirely arbitrary and can be basically described as: "we only use languages that we know and that management wants to promote".

Case in point: Dart is approved for use throughout. Go and Rust are unapproved.