First off, I listen to the radio call, so I didn't hear Timmerman's comment, but...
What I'm taking from the comments by people isn't so much that Timmerman said Ogbu was born outside the US, it's that he couldn't even be bothered to remember which country Ogbu was from. I doubt people would be ragging on him so much if he had said Ogbu had grown up in Nigeria before moving to Bismarck.
That's also why your example doesn't work. Since Australia is name of both the country and continent, it's not the same thing as Timmerman saying, "Ogbu is from Africa."
At least that's my take on things. Like I said, I didn't hear him say it, so maybe his tone of voice or phrasing was even more racist/stupid.