I guess it depends on your underlying viewpoint towards markets and capitalism. I certainly don't think liquid financial markets and efficient asset prices qu

I guess it depends on your underlying viewpoint towards markets and capitalism. I certainly don't think liquid financial markets and efficient asset prices qualify as "contributing nothing to society". Those components are extremely critical to the efficient allocation of investment capital, and overall functioning of the broader economy. But if you're generally skeptical of markets and capitalism then you may not agree. However I'd say that should have a lot bigger fish to fry than the $2 billion HFT industry. For example the $300 billion advertising industry, or the $100 billion accounting industry, or the $100 billion credit card industry.