Docker author here. Yes, the ability to produce a single binary that "just works" is one of the reasons we chose Golang. The operational simplicity is hard to beat, and you don't have to convince python hackers to install gems, java hackers to mess with virtualenv, and so on.

For the record, another reason we chose Golang is because it was not python. Docker is a rewrite of a 2 year old python codebase which has seen a lot of action in production. We wanted the operational learnings but not the spaghetthi code. So we made it impossible to cut corners by changing languages. No copy-pasting!