Wouldn't the corollary of Friedman's position be that if businesses take actions that people in society find offensive (such as preying on vulnerable individuals), that those people should therefore work to change the law?
I think Friedman's point was more that 'businesses' don't make decisions, people make decisions, and there are two classes of people involved - the people who own the business(principals), and the people who run the business on their behalf (agents). His article argues that the agents should carry out the principal's wishes (which does can include ethical concerns), not their own.
"Of course, the corporate executive is also a person in his own right. As a person, he may have many other responsibilities that he recognizes or assumes voluntarily–to his family, his conscience, his feelings of charity, his church, his clubs, his city, his country. He may feel impelled by these responsibilities to devote part of his income to causes he regards as worthy, to refuse to work for particular corporations, even to leave his job, for example, to join his country's armed forces. If we wish, we may refer to some of these responsibilities as "social responsibilities." But in these respects he is acting as a principal, not an agent; he is spending his own money or time or energy, not the money of his employers or the time or energy he has contracted to devote to their purposes. If these are "social responsibilities," they are the social responsibilities of individuals, not of business.
Much of the best writing I have seen regarding the relationship between individual 'virtues' and economic growth is Deirdre McCloskey's "Bourgeois Virtues: Ethics for an Age of Commerce"
http://www.deirdremccloskey.com/academics/