Their study shows that due to inherent biases in the way hedge-fund databases compile results, the industry's returns have been about half as strong as they appear http://finance.yahoo.com/news/buzzkill-profs-hedge-funds-half-145947680.html?l=1
The average professional footballer does not play in the Premier League. The average pro tennis player doesn't win grand slam tournaments. The average investor in anything probably loses money over time...the average hedge fund is probably the same. So who cares about the average?