No, it was not too complicated. You did not read the brief. The brief states, that they, the officers, are required to disobey lawful orders? There is already in the UCMJ, the order, not to commit crimes if ordered to do so. From your brief.
Too complicated? I am reading and quoting from the link you gave. It seems you are the one having a problem grasping what you linked to.
The service members are already required to disobey unlawful orders? So how is it that the court must rule Trump is not immune, to save the military from anarchy? By law, the UCMJ, there is a duty to disobey.