Honestly, there's still a point there.

Having a well-priced, liquid stock market is obviously important. Mises even set it as his threshold for socialism - a country that has an independent stock market is not socialist.

But that's not the same as appreciating the current state of stock trading. Sinking millions into millisecond improvements does not improve pricing. Identifying large trades and running pump-and-dump just before they clear doesn't improve liquidity. Running years-long fraud to get early leaks of Fed decisions helps no one.

A lot of what happens in high speed trading today is actually harmful to the market as a pricing and liquidity tool. Insider leaks from the Fed weaken market confidence for everyone. Flash crashes are a new horror born entirely of algorithmic trading. The list goes on.

I think it's entirely reasonable to appreciate free markets, even libertarian economic policies, and still consider the start of trading today alarming and detrimental to the economy.