Well, yes. They're called Cons. Just because they don't make direct arguments for repealing child labor laws doesn't mean they wouldn't do it in a heartbeat in the name of the "free market."
How many times have you heard the claim that some government regulation -- say, the cap and trade bill -- is really just a "hidden tax" because it will increase the cost of production for a company and therefore we'll pay more for their products? Sometimes it's stated without it being a tax, just that given policy X is bad because it will increase the cost of doing business and cause goods to cost more.
And of course, no one really wants to pay more for a product, right? But it seems to me that this argument, by itself, is pretty meaningless because it is equally true of government regulations that we all support. Forbidding factories from using child labor increases the cost of doing business and drives up the price of what is being produced; would anyone like to repeal those laws and allow child labor again?
But Ed's clever in using this argument, as it's one they can't get away with baldly refuting. There is a moral. And more ammunition. Go enjoy.