"Only a person in their chain-of-command can initiate action under the UCMJ. I am trying to ascertain who that was or which unit the person commanded. As someone pointed out, this could have been handled with a non-permanent letter of reprimand which would not have had any professional impact......"
I have yet to find a source for the info [underlined above]. Do you have any details?
Someone else named him above, Army Maj. Gen. Charles Cleveland, SOCCent commander. Like all combatant commands, it's a mixed service command, which explains why he's an Army General. He's the final uniformed commander in the SEALs chain-of-command, before the SECDEF.
The SEALs were offered Admiral's Mast - which is non judicial punishment, also known as Article 15. They exercised their rights under the UCMJ to refuse the Article 15 hearing, and demand trial by court-martial - special court-martial in this instance. Army Maj. Gen. Charles Cleveland is the convening authority for this proceeding.