As an addendum to a comment I left on a post this morning by Prof. Dunleavy, here’s a bit of Harry Blackmun from Virginia State Board of Pharmacy v. Virginia Citizens Consumer Council, 425 U.S. 748 (1976).
“There is, of course, an alternative to this highly paternalistic approach. That alternative is to assume that this information is not in itself harmful, that people will perceive their own best interests if only they are well enough informed, and that the best means to that end is to open the channels of communication rather than to close them.”
Blackmun was writing the rationale for allowing pharmacists to advertise the price of prescription drugs, but that paragraph is all about the marketplace of ideas. Information is never harmful in itself. It’s in the way that you use it.