Lots of things are. Defining what is and isn't detrimental to 'good order and discipline' will never be a sergeant's job. Ignoring 'counseling' for an apparently capricious reason is the reason this guy got bounced. He got what he wanted, and will likely get the OTH upgraded to a general but for a good while he'll be screwed. The Corps isn't a debating society.
Capricious use of UCMJ has nothing to do with the USMC being a debating society.
Disobeying lawful orders and creating disorder in the military are serious issues.
Expressing displeasure with the President through a silly rant, really isn’t a serious matter.