and a questionable marriage... the Obama romance. Southside with You
They couldn't find an African-American with the right shade to match Barry. And though the foreignness of his name may be addressed in the movie (see her father's reaction to the name), it seems the movie attempts to make Barry a normal African-American rather than the privileged child of the Dunham family who happened to have an African for a father.
And they also did a job on Michelle, making her more likeable and warm than she really is.