Talking of straw arguments, I don't see John Langford saying in this article that anyone has gone so far as to claim AlphaGo is an AGI. What I have seen is a number of comments on HN kvetching about moving goalposts.
Well a bunch of people were confused and still don't know the difference between AI and AGI.
I actually think it's OK if some people think AlphaGo is more general purpose than it really is, because the general attitude or at least appropriate response to the likely development of AGI relatively soon still seems to be amazingly muted.