^I do think that to discuss these things with specificity we have to draw a line at how attenuated the causality link is. I certainly don't hold Walt responsible for "the thousands of people who used his product" or "the gang violence that arose from his drug empire." Yes, he is what the law calls a "cause in fact" - that is, he was part of the chain of events - but he was not a "proximate cause" of those things, any more than he was responsible for the airliner crashing because he didn't intervene to save the daughter of an air traffic controller. I just don't lay that at his door. These things would have happened anyway, in some form or another.
As for things Walt directly did, like making the boy sick... maybe I should have a problem with it. But somehow, the way it was presented on the show, I don't. I don't know if that's a function of the tv presentation or an indication that I'm a sociopath. The former, I think.