Socially Responsible Investing - Just a Fig Leaf?

While it may hurt investors in the pocket, are they not the ultimate responsible party on the way to socially responsible business practises? If yes, can they stay aside when a company tries to squeeze the last dollar out of its product, however reasonable the may be following simplistic principles of capitalism? Or should there be some restraint based on ethical consideration even if it if against full-out profit maximization? What would one say if doctors create a monopoly in heart operations and use every possible legalistic trick to prevent competition thus being able to increase their fees to some astronomical level?
(18-Oct-2017)
Bloomberg