Generally I use standard library, with the exception being github.com/gorilla/mux Gorilla Mux for routing because it removes so much boilerplate.
I do however use Python for all HTTP integration tests. With requests + voluptuous its so much more productive than doing them in Go, which I had previously done.
Go is great for systems programing, building kubernetes, CLIs, etc.
It is very far from being a good idea to use it for general web development. Right tool for the job and such.
I agree is not ideal if you want a full-blown monolith web app. In that case a typical MVC framework will save you weeks.
Even if it is just a rest api, you still need a database/ORM layer, a validation framework, a migrations system, a way to document it, etc.
So, from a developers life quality and company economics point of view, django or rails are way, way more performant, but not as cool I agree.
Sure, if you're building Facebook or google Go might be the best option.