You noticed the same thing I did. I was under the impression that if an enlisted was courts-martialed then the accused could elect to have up to 1/3 of the courts-martial panel be enlisted, so long as they were not a junior rank. This trial had 1/3 officers, 2/3 enlisted, leaves me a little confused.
The old rule of thumb was never elect to have any of the panel enlisted. They would be an E-8 or E-9 and tend to opt for a harsher sentance than an officer.
I still remember the rule of thumb you describe which is why I found the composition astounding.
So much has been written by so many people who have conflicting opinions on this entire issue that I opt to accept the outcome of the Judicial action. Moreover, the reviews and appeals that will follow will allow a fair outcome.