Most of the projects I come across for Go are for things that traditionally have been in Ruby/Python's camp. Examples of these are web infrastructure and command-line stuff.
Rust, on the other hand, seems like its being used more for things that have been done in C++. i.e. rendering engines and operating systems.
The comment author never stated that Go is better than Ruby/Python. The author points out that a lot of Ruby/Python people have switching over to Go... seemingly more than to Rust.
This isn't a statement for or against either projects worth.