I think he’s a V. They look human (sort of) but they’re not, and all nuances of feeling or connotation are lost on them. If “V” weren’t fiction, that would be my choice!
Seriously, though, he’s not what he says he is (he’s neither “African American” nor “American,” and he’s sure not “Christian”), he’s not very smart, and he’s entirely in his own world...must of which involves hiding his past from the people of the United States.
So I can see that he might be a little stressed and prone to blow it on the meaning and use of certain expressions.
I’m a linguist, and it’s rare for native speakers to get these things wrong; it happens, but then they will usually correct themselves. Near native speakers (highest level of proficiency for a non-native speaker) do it occasionally, and generally don’t recognize it until later.
The other people who occasionally have trouble with the affective meaning of phrases are people who have severe emotional problems (such as autism) or people who have had brain injuries. I’ve always wondered about that scar on the right side of Bambi’s head.
This is my point. A normal person who misspeaks, whether it's Biden or even George W. Bush, would IMMEDIATELY correct himself, a la Biden's famous Up Chuck comment, where his cover was hilariously over the top. "Oh NO, what am I sayin'?? EVERYONE, stand up for Chuck!"
I bet Obama never even bothered to think about what he had said. And doesn't care right NOW. He will wait to see how big any uproar over this will be, and not make a correction unless he really "has" to. He cares not.