That's completely untrue. Zero Hedge breaks news before a lot of outlets and writes on a lot of market events that other sources will not touch. I'm not disagreeing that you need to have a filter when reading but they absolutely do provide value.
Any examples?
Gold price spikes down, it's the HFT slamming it because they work for the Central Banks. Gold price spikes up, it's because investors are concerned about the market.
Stocks spike up, it's the HFT again. Stocks spike down - investors start seeing that the whole market is a scam.
So the HFT trade only in the "wrong" direction according to ZH. They sell gold and buy stocks. Never the other way around. I'm exaggerating, but only a bit, there were a few articles which blamed HFT for "right" moves (gold up, stocks down).