what caused the character of the industrial revolution in the u. s to change from one of concern to one of exploitation?

The invention of the steam engine brought about the Industrial Revolution. This allowed technology to advance, and let farmers to be able to farm more land more efficiently. It also led to mass production of goods in factorys - before this, all goods were manufactered by one person. For instance, a shoe maker. Instead, they had huge pactorys, with unskilled workers, each completing one part of the shooe, as opposed to the whole thing.

So, basically, it was just technology advancing - like most revolutions in our society.