Well, I probably shouldve read the whole discussion so far, cuz this may have been mentioned. If it has been, forgive me....
But wasn't the point of "I, Borg", not that the genocide would be wrong, but that using Hugh as the instrument after he had regained individuality was wrong? The fact of the matter was that Picard changed his mind after he realized Hugh was capable of making the choice as an individual, that he had wants and preferences just like the rest of them. Everyone apart from Crusher agreed pretty quickly that the plan was right to do, it was the idea of using Hugh to do it that created the moral dilemma.
But you see, carlmarx, in 'I, Borg', PICARD DID COMMIT GENOCIDE!
Picard had a chance to stop the borg and he didn't use it, knowing
that the borg are and will continue to kill BILLIONS, in an orgy of violence, death and suffering beyond comprehension...
Picard either used the weapon against the borg (using Hugh), destroying the hive mind, or he didn't, in which case he, too, is responsible for the death of BILLIONS UPON BILLIONS at the hands of the borg.
One can only choose the 'lesser evil' in this situation; there's no moral, 'white' choice.
Picard allowed the borg to endure, staining his hands with the blood of BILLIONS. Picard choose 'the GREATER evil', by far.
And why did Picard do this?
He did it in order to delude himself that, even in this situation, he made the perfectly moral, 'white' choice. So he took the choice that had the APPARENCE of being 'white', moral.
As for the BILLIONS the borg continued to kill, well, if Picard didn't have to see their faces as they died, he can keep telling himself they're not his problem, that their blood is not staining his hands, too.