It's an opinion. A very compelling and well researched opinion. I wouldn't be remotely surprised if it was true but until we have concrete evidence it's still conjecture.
If the full story ever does come out, it's going to feel like ancient history.
One of the things that I think is that potentially it might not change much. Fact is we're already at the point where the lost gox btc has been accepted as lost/hacked/unrecoverable etc. Now if this isn't going on on other exchanges the price we're at today is a 'fair' price. Only time will tell what the market thinks. I'd expect at least an attempted panic retraction but in terms of the price today what does it change?
But what if this becomes mainstream? I think that if popular news agencies cover this story the general public will start having doubts about the price bitoin has today. Maybe resulting to a nother fall.
It hasn't come from the mouth of anyone related to Gox or any mythical hacker or any legal entities. It's one guy's thoughts.
If it inspired a journo to go out and prove that it was the stone cold truth, then we're off to interesting places. The longer it all takes for the truth to emerge, the less potential impact there could be.