I call it vigilantism because he sees these things that are classified and thinks people should know about it, so what he does is takes the law into his own hands. He decides he has the right to unilaterally decide these documents are no longer going to be classified, though the law specifically says he doesn't.
The type of civil disobedience we think of with MLK, Rosa Parks, or the anti-war movement does involve breaking laws, but it does not involve taking the law into your own hands.
Look at it this way. If you protest a war by going to a sit in and getting arrested, that's civil disobedience. If you destroy a military storage facility full of weapons and vehicles about to be shipped overseas because you don't think we should be in the war or sending these things over there, that's vigilantism.