Does it also extract methods, convert fields into accessors, move code between packages while updating import statements, update comments that relate to code, move methods across types?
This person is just wrong. It's not because the tools weren't there or the commenter was unaware of how they work, that Go is bad at refactoring. It's very easy to write correct, type safe refactoring tools on Go code.
http://golang.org/cmd/gofmt/
It allows easy renaming of variables, constants etc.