Monsieurrenard,
I actually am rather young (19,) but I don't think that this is why I don't understand what a 'wage slave' is. I don't understand because you haven't given a clear definition of it. Even the site you linked to admitted it was a nebulous term. Honestly, I'd group it with terms like 'price gouging.' Items that people can feel passionately opposed to without really knowing exactly what they are. Can you give a clear definition of what constitutes a wage slave?
I also can't agree that my positions are due to my youth. All of the views I hold are the views that most mainstream economists hold.
The items that you list as failures of capitalism really need to be sorted into two groups. The first are market failures. This includes monopolies, health standards and environmental impact. Monopolies because they by definition lack the choice and competition that a free market has. Health standards because without them, a consumer will lack the knowledge(whether this particular product is safe to eat) to buy the food they want. Environmental degredation because of ill-defined property rights (ie no one owns the air, so no one has the incentives to keep it clean.)
The other items are not examples of market failures. An outraged union tells us nothing other than the fact that the union is angry, not whether there's a good reason. Child labor has nothing to do with corporations. It has to do with how wealthy a society is. Studies have shown that as soon developing economies get past survival level incomes, child labor drops very quickly. Unrealistic work hours is a silly claim. No one has to work 70 hour weeks. People do it because they want the money. Our first world countries are so well off that we'd rather have the free time than the extra income, but if you can barely feed and clothe your family, a 7 day work week is very attractive. I have no problems with the idea that the markets are imperfect, but it's not as simple as bad situation=market failure. I need to see a reason why the market isn't able to address this need and then proof that government can meet it better than the market.
As far as US history is concerned, it'd be more accurate to say that the US moved away from a purely Free Market during FDR. I could go into how absolutely damaging that was to our nation(both in prolonging the Great Depression and in abusing the Constitution) but that would be better saved for another thread.

It's certainly not easy to sit hear and argue that it's ok to pay Chinese workers a low wage. It'd be much easier to blame a scapegoat for the fact that the world isn't ideal. If Wal-mart doesn't 'take advantage' of the situation, what will happen?
1) Corporations won't invest in poor economies. This will slow down the growth and development of infrastructure and keep the nation poorer for longer.
2) Corporations pay Chinese workers comparable rates to American workers. As with number one, corporations won't invest in poor nations. They'd be better off investing in America, since we have a stable government, a more productive work force, and no costs for transportation of goods(assuming they're to be sold here.)
3) Corporations don't pay Chinese workers the same salaries as Americans, but still raise their wages. If the cost of labor rises in China(without any corresponding increase in productivity,) projects that previously would have been more profitable in China move to America. China gets reduced investments, and fewer positions in sweat shops would be available(although the ones that
do exist would pay better.) Since sweat-shop jobs are already high-paying compared to the rest of China's economy, this would essentially be a redistribution of wealth from the Chinese that would have had jobs in American-owned factories, to the ones that still have their jobs. Robbing from the poor to feed the less poor doesn't sound to attractive to me.