Let's just take Saville's "facts" as read. He is, after all, a judge, and his job is to presume innocence and only declare as fact that which is proven — which puts those who are willing to tell the truth about their actions at some disadvantage. So fair enough: we'll say the facts are as Saville describes them. His reasoning is still bollocks.
Those rules of war so disdained by the Left when considering our enemies are there for a reason. Yes, if you keep chucking paras into crowds of civilians with terrorists hiding amongst them, sooner or later you'll have an atrocity on your hands. Which is precisely why not wearing uniform is a war crime, why hiding amongst civilians is a war crime, and why the traditional (and legal) punishment for being caught by the enemy out of uniform on a battlefield is summary execution. I believe Saville is right that the soldiers who fired had no reason to suspect that the particular individuals they killed were about to attack them. But the cases of Martin McGuinness — who had a Tommy gun but didn't directly use it in a way that justified the soldiers' opening fire — and Gerald Donaghy — who had nail bombs but was not shot because he had nail bombs — show the absurdity of it all.
No. The fact that Donaghy had nail bombs and was dressed as a civilian and was in a crowd of civilians may not be why he was shot at that moment by that particular bullet by that soldier, but it is very much why soldiers were pointing guns at civilians in the first place. Does anyone seriously think Bloody Sunday or anything like it would have happened had the IRA worn uniforms that distinguished them from ordinary members of the public and refrained from mixing with the general public while on duty? That the army, faced with an identifiable enemy on a battlefield and an entirely separate crowd of civilians several miles away, would have chosen to shoot at the civilians? To ask the question is to ridicule it.
Remember this the next time some romantic eejit excuses "asymetrical warfare". Of course fighting out of uniform gives you a huge advantage; of course hiding amongst non-combatants gives you a huge advantage. Such tactics would give anyone — the British, the Israelis, the Americans — the same advantages, yet they don't use them. There's a reason why civilised people disallow such behaviour, and that is that every single time you step into battle disguised as just another member of the public, you make Bloody Sunday more likely.
Just because it's someone else's fault, doesn't mean it's not yours too.