Blackman case a "watershed"?

The Times of London has this piece by Ewen Southby-Tailyour, a retired Lieutenant Colonel in the Royal Marines, about the Court Martial Appeal Court's decision in R. v Blackman. The headline: "Watershed case puts military justice in block."

The Editor's opinion: Lt.-Col. Southby-Tailyour has not made the case in any sense. Indeed, unless I am misreading his article, he seems to be inviting prosecution for, as he says, "help[ing my sergeant-major] to die" in Oman in 1968. How analogous is that to shooting a wounded enemy combatant?