The reason is plain: Obama is a politician.
Like most members of the species homo electedofficialus, Obama’s expertise lies not in actually distinguishing real from imaginary problems, and then in forthrightly and sensibly addressing these. Instead, he is expert only in what Plutarch called “the base and dishonest buffooneries of mob eloquence.”*
The only mystery is why someone as intelligent as Ms. Marcus is surprised by this fact.
* Plutarch, “Pericles,” in Plutarch’s Lives, Vol. 1 (New York: The Modern Library, 1992), p. 204.