Consumers do not think about the labor force unless they are forced to do so.
Precisely. And that really underscores why changes (such as some here are advocating for) must be a reflection of a change in consumer thinking - a change in our society's mind-set. Such changes are often reflected in our laws.
It is pretty clear that Americans care
No: It is clear that Americans claim to care. Some Americans really do care, I'm sure, but the reality of how things are clearly shows what Americans, in general, do and do not care about.
which is why many labor practices have been made illegal
To be clear, no one is saying that Americans don't care about anything. My point is that Americans currently don't care enough about
this to justify the expectations that some in this thread are voicing.
But how quickly did Americans react when they found out that some of Oprah's merchandise was being made in sweatshops overseas?
That's actually a funky situation, and one that I think shows a very negative side of Americans (not to say other folks aren't also as guilty of this): In many cases, they will only get steamed up about something if they're incited to riot (figuratively speaking), spurred on by irrational chest-beating - the whole "Think of the children!" phenomenon. That's not the say that there aren't cases (such as perhaps the example you gave) where that rather mindless mob mentality is applied toward good aims - things that if people really sat down and thought it through, they'd still be as incensed - but my impression is that the vast majority cases where this kind of pitchforks-and-torches approach is applied are cases where it is just one set of people trying to make their own personal preferences sound more important than they really are. They're essentially just trying to incite people to riot, because they didn't get their own way on the power of the merit of the issue.
Even with the example you mentioned there are clear indications of this: Don't think Oprah's merchandise is the only overseas-sweatshop merchandise purchased by the people who got up-in-arms. Most of the folks who got upset weren't really passionate about the underlying issue - they just wanted one or more of the visceral thrills that they were able to derive from being upset: Either feeling part of something vital; the charge they got from taking a shot at Oprah or who/whatever; and/or the reward of feeling like they did something praise-worthy, even though, in the context of their purchasing habits overall, that one part was practically insignificant.