I don't think many people subscribe to this idea at any kind of extreme. No one's going to say "Well, you saved 50 people from certain death during a disaster last month, so it's okay that you murdered that one guy today for cutting you off in traffic".
Yet it's still an interesting idea, in some ways. It reminds me of various other sayings, like "the ends justify the means" or "the needs of the many outweigh the needs of the one". Or an Ursula LeGuin short story, "The Ones Who Walk Away from Omelas".
Usually, people accept a certain amount of negative consequences in return for desirable things. One could assign a portion of the blame for the deaths from every airplane crash to the Wright Brothers, or hold Henry Ford partly responsible for the tens of thousands who die in car accidents each year. But we don't look at airplanes or cars in terms of the damage they do: we look at them for their benefits instead. And those benefits can be measured not just in convenience, but in human lives, too. Famine in the modern world is not a matter of food production, but of transportation: improving technology in this area has helped tremendously.
It's easier to forgive unintended consequences, though. Plane crashes and car accidents aren't an essential part of faster transportation: indeed, people make changes to them all the time to make them safer. Which is one of the benefits of the drive and ambition of modern society: we're never satisfied.
But it would be different if the negative consequences were not unintended, or if they wasn't even an apparent connection. Rapists aren't the price we pay to have an effective military, and to say that they are is an insult to every man in uniform. The two don't go hand in hand .... necessarily.
But what if it happens that they do? What do you do with someone who is mostly good, who has done great things that few could match -- but who's also done something terrible?
At what point does the hero become a villain? Which flaws can you overlook? Is it okay if the firefighter who's rescued hundreds of people from burning buildings cheats on his wife? What if he beats his children? Maybe he's a chronic shoplifter. Maybe he got a co-worker killed once, by accident, and then covered up his part so he wouldn't get blamed or lose his career. Does the good that he's done make the evils more forgiveable, or less?
What if the events really are correlated? What if that cop really did need to torture his captive in order to find the location of the bomb that would otheriwse kill hundreds?
Or is that a hypothetical case that never matches reality? Does evil ultimately beget evil, even if the intentions were good, so that truly no good comes out of a sinister act?
Sometimes when I think about all the horrible things we hear about people in power, the way no presidential candidate can escape attacks upon his character, and I wonder if they're all true. If that's the way everyone would look if they were put under a microscope to be viewed by 300 million prying eyes. All those flaws, amplified and expounded on and presented in the worst possible light. How would I look, under such scrutiny?
Is the problem with stories that they only present a tiny portion of the whole? We ascribe such weight to the things we know, but in every person we judge, there's a lifetime of experience we do not know.
I don't know where I'm going with this. I don't have any answers, only more questions.