The man had a stellar career before M5 freaked out, so I can see him getting some slack and the blame beign shifted around to cover a lot of asses. He takes a 'retirement' and all is well and reps are intact.
That goes beyond mere courts-martial and into the realm of a government changing hands in the next election.
Fat Chance Productions presents: that happens only in simulations. In reality, the party in power that caused the debacle spins the whole thing in the media so that it becomes the fault of another political party that had nothing to do with it. Unlike M5, the guilty have no scruples to hamstring their ambitions.
Or you claim that Klingons/Romulans hacked the computer and only the bravery of the Enterprise crew managed to uncover and neutralize the sabouter before more deaths were caused.