Sort of an unusual article I would say.
I did not see any source of the diary page in the article. How was it obtained being I would consider that being a private document.
Why was it released being private thoughts of the president?

Was this planted by the Obama campaign team for political gain?

I would toss this off as fiction without the above questions answered.

JAP69 is correct about it being fiction. Unless Obama lies to himself in his diary, the sentence "Awkward run-ins with Wright, Ayers, Daley" is the dead give-away.

Bill Ayers and wife have been frequent visitors to the White House as visitor logs will show. They are still very much friends, so running into him in Chicago would not be awkward.

if he had a diary, it would be for sale and the mindless followers would be eating it up.