I suspect they intentionally dual-branded it, officially calling it "Go" but hosting it at golang.org, giving the contrast to Erlang's name. They might want the

I suspect they intentionally dual-branded it, officially calling it "Go" but hosting it at golang.org, giving the contrast to Erlang's name. They might want the option to trademark it in the future, so couldn't use "Go", just as Coca Cola couldn't trademark "Coke" because it was a common word.