Well returning to the argument of whether or not the officers of a corporation are actually mandated by law to maximize profits for shareholders thus restricting them from other considerations such as responsibility to workers, the community, the environment, or even morality, looking at just summaries of the laws (Sherman Anti-Trust Act, the Securities Act of 1933, the Securities Exchange Act of 1934 and Sarbanes-Oxley) barryem cited I do not see anything that would restrict corporate officers from considering other factors then shareholder profit even to the detriment of profit. Nothing of the sort in the summary of the intent of lawmakers when these laws were passed. Then I'm definitely not a lawyer.

I can only say that regardless of law makers intent at the time a law is passed, and even regarding changes in how the law is later interpreted, what in practice a law means really depends on what the enforcing authorities (executive and judicial branches of government) choose to say it means, and that definitely can change with the political environment. How historically the 14th Amendment has been interpreted in scope and intent provides an excellent example. I feel that there can be little doubt as the article cited by SteveEisenberg states that over the last 30-40 years interpretation has very much shifted in favor of the owner/investor class to the detriment of all else.

Regarding Walmart the criticism of that company is not just that they have put smaller competitors out of business, it's that they have in part done this through driving down worker wages and other compensation to the point that those workers must rely on public benefits, effectively a government subsidy for Walmart's business practice.