That's stretching the definition quite a bit. A bit too far IMHO.
I'm not a military law expert, so I really can't elaborate more except to say that it's obviously not treason.
Has anyone in the US ever been charged with treason for refusing an order?
UCMJ has a different category of offense for that. The charge isn't
treason.
Article 92:
892. ART. 92. FAILURE TO OBEY ORDER OR REGULATION
Any person subject to this chapter who--
(1) violates or fails to obey any lawful general order or regulation;
(2) having knowledge of any other lawful order issued by any member of the armed forces, which it is his duty to obey, fails to obey the order; or
(3) is derelict in the performance of his duties;
shall be punished as a court-martial may direct.
Article 90
ASSAULTING
OR WILLFULLY DISOBEYING SUPERIOR COMMISSIONED OFFICER.
Any person subject to this chapter who--
(1) strikes his superior commissioned officer or draws or lifts up any weapon or offers any violence against him while he is in the execution of his officer; or
(2) willfully disobeys a lawful command of his superior commissioned officer;
shall be punished, if the offense is committed in time of war, by death or such other punishment as a court-martial may direct, and if the offense is committed at any other time, by such punishment, other than death, as a court-martial may direct.
ART. 99. MISBEHAVIOR BEFORE THE ENEMY
Any person subject to this chapter who before or in the presence of the enemy--
(1) runs away;
(2) shamefully abandons, surrenders, or delivers up any command, unit, place, or military property which it is his duty to defend;
(3) through disobedience, neglect, or intentional misconduct endangers the safety of any such command, unit, place, or military property;
(4) casts away his arms or ammunition;
(5) is guilty of cowardly conduct;
(6) quits his place of duty to plunder or pillage;
(7) causes false alarms in any command, unit, or place under control of the armed forces;
(8) willfully fails to do his utmost to encounter, engage, capture, or destroy any enemy troops, combatants, vessels, aircraft, or any other thing, which it is his duty so to encounter, engage, capture, or destroy; or
(9) does not afford all practicable relief and assistance to any troops, combatants, vessels, or aircraft of the armed forces belonging to the United States or their allies when engaged in battle;
shall be punished by death or such punishment as a court- martial may direct.
FWIW, none of that is
treason, though some of it may be
cowardly or dishonorable.