The essence of the point is that Free Markets will allocate resources to the most favorable environs for profit. Whereas Free Enterprise means maximizing the advantage of such environs, even if by impinging the basic rights of such locale as defined by the most comprehensive body of rights represented among involved parties.
Too often corporations hide behind the banner of Free Enterprise, counting on fools to misunderstand the subtle differences between it and Free Markets for the purpose of returning shareholder profit at the cost of the local citizenry, present and future.
Examples include Apple's Foxconn workers jumping from buildings after enduring unsavory working conditions for years, among others.
It is most important, even for a libertarian, to recall that without affording others our version of basic human rights we are animals and hypocrites. Too, corporate profits measured against human suffering should duly taint all bearers' karma.