Even slavery had its defenders- in fact, it still does. If you read any story about chocolate slavery, there will be comments in support of it. Defenders of Apple's use of sweatshop labor in China are in the same position, defending the indefensible in the name of profits and efficiency.
If you believe in any human values at all, you will not believe that sixteen hour shifts and a seven day work week are excusable on any grounds whatsoever. If a company cannot make a profit or stay in business without those types of labor practices, then it has no right to either earn a profit or stay in business. Making a fetish out of profits and efficiency is a modern kind of idolatry, and those who worship those particular golden calves will defend their false idols with every rhetorical trick in the book. That doesn't change the reality of what they are doing. They are the moral equivalent of apologists for slavery, and their position is as inexcusable as they practices they defend.
The workers at Foxconn (the company that makes Apple products in China) have threatened to commit mass suicide if their conditions are not improved. Just stop and think about that before you give me another smug explanation of how I don't understand the realities of capitalism.
Apple products are superior products. That doesn't excuse them even one iota from their moral responsibilities. If you love the products that Apple makes, as so many people do, then you should join the campaign to pressure them into improving the conditions of their Chinese labor force.