That's like saying that there's no meaningful sense in which I, apart from my brain and nervous system, make decisions about what my body does.
There is more to Go than Google, there is a community and it is as free as can be. But the final decision makers are at Google. It's all very well said, every open source project has a set of final decision makers and that project is theirs. Unless you work hard to become one of those decision makers the project is not yours. And perhaps it is not notable to write the blog post "this open source project ACTUALLY belongs to so-and-so."
For me, the more convincing argument is that Go would have probably happened in a parallel universe as well. Imagine that Griesemer, Pike, and Thompson had worked another company that gives the freedom to work on personal projects, it is very likely that they had come up with the same language. They have argued in talks that Go was created as an answer to problems that they identified in the development of infrastructure at Google. That may have been a trigger, but Go is firmly rooted in the tradition of C, UNIX, Plan 9, and Limbo and a logical next step in that tradition.
Hence, to me, Go is really Griesemer, Pike, Thompson, and Cox' language and not Google's language.
Of course, the title of the original article that Taylor is reacting to was a bit sensational. But I think the original point was that Go is not a language that is developed by the community, but a small set of people. Whether they are employed by Google, Facebook, Uber, or Zalando is somewhat irrelevant to this debate.
I'm not certain, because - like I said - it's worded confusingly, but that was my impression.
I think you could say that about most teams at most companies. That doesn't mean that they have any autonomy whatsoever from their company, though.