Gentlemen, you're starting to forget the question being asked here: Was Picard wrong not to release that virus in I Borg? I say he was. Picard thought he had a sure way to get rid of the Borg once and for all and he didn't take it, thus possibly condemning billions to assimilation (Which, according to Picard's actions in FC, is worse than death). This make Picard the worst kind of coward, he was willing to put the Federation in mortal jeopardy just so he could do the "moral" thing.
It does not matter if the virus would or would not have worked, what matters is that Picard believed the virus would work. As Picard himself admitted, the moral thing to do is not always the right thing to do.
Let's also not forget that the question being presented is a subjective question that is different for each person answering it. There is no one mathematical, cut and dry answer to the question, because at the same time, what is "Moral" is also subjective to the individual.
The "Moral" thing to do is not always the right thing to do, yet the "Right" thing to do is dependent on what morals one believes in.
When someone believes the "Right" thing to do goes against a "Moral" thing, their determination of what is "Right" is directly related to that person's own "Morals."
It's a bit of a "Chicken and the Egg" Complex. Why you feel something is more right or more wrong then something else, is dependent to your own pre-set morals.
Which means there's no one true answer except the one you as an individual believe in. I can not tell you it is wrong, because then I'd be imposing my own pre-determined morals, just as you are doing trying to tell me my view in Picard being right is wrong.
It's all based on opinions on a situation that has no real true answer.