BECAUSE TRUTH COULD HAVE SWUNG THE ELECTION... SUCH WAS NOT REVEALED
... and instead remains concealed to this day
Obama is protecting Hillary who will likely soon resign in order that her 'unblemished' record support her candidacy for either president in 2016 or prior for SCOTUS (Billary too then Elizabeth Warren once sufficient 'experience' as a US Senator is acquired).
That's the reason and.... the plan.