The initial comment asked for the benefits of HFT. All that comes up is that it improves the performance of markets. If you need economic growth it is a good thing to have efficient markets, incentives to invest and be rewarded with a share of the growth you enabled with your investment. But without the need for economic growth it just becomes transferring wealth from the workers to the usually already well-off investors increasing wealth inequality.
I would not say that capitalism is bad per se. It is pretty good at what it does and I find it hard to imagine that we could have made the economic growth and reached today's level of wealth without capitalism. But it has its flaws and I see no way it is sustainable for much longer. And instead of recognizing that we can not grow forever and seek for a transformation to something more sustainable it seems to me we are pushing capitalism to its ultimate limits. Not stopping until hitting a brick wall. HFT seems an iconic example of that to me.