As far as I know there are very few laws regarding profit margin.
Also, I don't believe "profit at any cost" on a personal level. I don't even believe in profit at any cost for corporations. I believe that some money should be poured back into R&D etc.
But you're dead wrong in your view of companies. They really are "machines." If you expect them to act in a moral fashion then you're in for a lot of disappointment.
Companies don't have a will of their own, nor a conscience. The peeple running them do. And, yes, they are expected in America to operate in an ethical fashion. It just seems that many more nowdays resort to what they can get away with instead of doing right for right's sake. But, then, that is what we get when people abandon proper ethics for money.