True enough with respect to the processes for classification and declassification. The President expresses his authority via Executive Orders and other directives. EO 13526 does exactly that and even lays out specifics for sitting and former presidents. It lays out the conditions for declassification and "so I can read them on the john" is not amongst the reasons.SCOTUS has already had rulings on this topic.
“The Supreme Court confirmed as much in its 1988 ruling in Department of Navy v. Egan.”
"[The president's] authority to classify and control access to information bearing on national security … flows primarily from this constitutional investment of power in the president and exists quite apart from any explicit congressional grant," the court said.”