Your point is absolutely true and valid. But there are no realistic alternatives. Take apart a Dell or HP machine (and I do often) and all the parts were manufactured and assembled in factories in China. Even if you buy locally assembled machines (and I do sometimes), the parts themselves all come from China. And I need a lot of computers for our work unfortunately.
I have been cutting back on my personal Apple product purchases though.

I went through a crazy phase when I bought a lot of their stuff in a short space of time. iPhone, MacBook Pro, Mac Mini, iMac, my iPod and the AppleTV. I think all of those came in a 6 month period when I was very excited about Apple gear in general. Since then, I have resisted the new iPods, the iPod Touch, the iPhone 4, the iPad etc. I have no interest in buying one of the new MacBook Pros. Or the Mac Minis with HDMI port. And I definitely won't be buying the new iPad. So maybe I have woken up after getting caught up in the initial excitement stemming from the iPhone.
To be honest, I never really thought about all the issues of cheap labor until after I bought most of my Apple products. I'm not proud of that fact. You are absolutely correct that it is people like me that encourage the kind of corporate behavior that goes on. I absolutely have a responsibility to consider whether I want to buy products from a company that makes all its stuff on the cheap in countries like China. And it has had some affect on my purchasing decisions recently at least.
I'm still glad that I have the choice of buying Apple products or not, than
having to go to work for them each day to earn a living though. I have always been far happier doing good work for private companies.