Friedman's response to this was that there is always cost to some policy. The cost of protectionism just happens to fall on the majority of people which have no particular voice.

Protecting the local steel industry might be good for the steel workers, but it raises prices for everyone else in the economy who consumes steel. Now certainly every time someone's job is disrupted by competition it is personally tragic, but why do the interests of one particular interest group weigh in larger than the well-being of everyone else?