alt Hacker NewsThe thing is that doesn't even sound wrong and I don't think any native speaker would object to the article when used with a place of origin/belonging in a speech.
It emphasizes the statement if you ask me.
Only many years after learning of the speech I read online that it's allegedly "a gaffe".
It's uncommon, but without thinking about it, I wouldn't have noticed that I wouldn't usually add the "ein" here. I think it emphasizes the affiliation to the group of people.