This is nonsense. There are plenty frameworks, like the one discussed in this post. The lack of any kind of language feature has never stopped people from writing solid libraries, frameworks and applications in Go. Lots of examples out there.
I agree, especially when words like idiomatic are used it usually is very one sided perspectives. I know popular startups that use their own in house Go frameworks, and many of the devs there worked at Google, some on Go. They would use packages and make them appear like classes to other callers, etc... basically mimicking long proven design patterns in their frameworks.
Also, lots of dependency injection patterns everywhere, which is actually a great way when dealing with larger projects.
Well, the garbage collector makes it anti-embedded but otherwise I agree with you. Languages aren't "high level" or "low level" they're whatever you and the community choose to do with them. The libraries that exist help speed that along of course.
(I know that the absence of generics is temporary)