Free speech is a good idea for game-theoretic reasons. That's it. Free speech lets people fight it out with only the occasional riot and attempted overthrow of the republic. That's better than the alternative.
It might not have happened yet, but I suspect we're heading in that direction. We've seen 'speech related' bans from Paypal and crowdfunding sites.
Paypal even deplatformed the (UK-based) Free Speech Union (although they reverted that decision after the backlash)
“Just build your own bank.” “Just build your own currency.”
To develop 'Social Network' or 'Digital Currencies', you need 'Server Farm', 'Internet', and 'Power Grid', and to have those you need everything from 'Intercontintental Data Cables' to 'Semiconductor Manufacturing', and way back to extraction and refining of raw materials..