This blend of slippery slope argument is all fine and dandy, but the key point of this discussion is that there are operational expenses and revenue and if your business plan depends on a never-ending inflow of cheap labor from people willing to work for below-poverty wages to drive down your operational expense then not only is your business model completely unrealistic but you also have to take a step back and seriously considering your net contribution to society.
I mean, think about it: why is a 1000$ pizza supposed to be a ridiculous idea but 8$/hour to make said pizza is not shocking? Is it reasonable to assume that the person making the pizza should be forced to work about 3 hours making pizzas before he could afford one of his own?
"You could do better if you raised prices a dollar" and "you would do worse if you raised prices a thousand dollars" can absolutely both be true. In fact, in many, many circumstances, they will be.