Re: "the marketplace of ideas", there is a modern philosophy that ascribes mythical qualities to markets, but the fact is that markets are not magic, they are merely useful tools that are appropriate for some contexts and inappropriate for others. There are numerous ways markets can either fail or be worse than useless, and one of those ways is by obscuring information about the market, and it's increasingly trivial to use unfettered free speech to effectively censor any other market participants, thereby distorting the market.