You are seriously confused.
General Casey, acting in his capacity as the JOINT commander of ground forces may order investigations throughout his command. These investigations are carried out by officers serving in Joint billets. Evidence obtained in such investigation may be used for criminal investigations if appropriate.
But, criminal investigations, and actions under the Uniform Code of Military Justice (UCMJ) are the responsiblity of the several services. No one in the Army acts as a General Court Martial Convening Authority (GCMCA) for someone in the Marine Corps. That is done by the Marine Corps Chain of Command. Any charges that have been preferred have been preferred by Marine Corps GCMCA.
LTG Kearney, acting in a JOINT billet as Commander, JSOC, ordered a unit under his command out of theater, an operational decision. Any UCMJ actions would be undertaken by the Marine Corps Special Operations Command.
Don’t try and drag the Army into this mess, its the Marine Corps $hitting in its own messkit. I share your concern about what appears to be overzealous use of UCMJ to play Monday morning quarterback over combat actions, but I haven’t seen the evidence in any of these cases and can’t say what conclusions I would draw if I were serving on the Court Martial board.
With one exception, I don’t disagree with you on any of your points.
This is a joint dump in the mess kit and murtha not only has all the shovels, but the toilet paper as well.