Maybe the decision to investigate/prosecute was influenced by embarrassment. It may have been only brought to light because it caused embarrassment. I don't know.
In my two posts on this, I've prefaced my statements with "IF". It's for the ALS to prove he "did it". Or possibly the CPS if it is dealt with the the Old Bailey vs GCM.
I'm not suggesting he should be hanged or flogged, I'm suggesting that this is a very straightforward situation. He either did, or did not commit the offence. It is a very black and white situation with regard to this type of thing.
Some things are open to interpretation in the military, and the higher up the greasy pole one climbs, the more latitude one has. Others are not though. Weapons, protection of classified information, insubordination, (amongst others) are absolutely rigid however, and deservedly so. This is not a mess do that got out of hand, and the Adjt dishes out a few extras and no harm done.
I've no idea about the US Military due process, I was Brit mil. And I'm still subject to the OSA.