It depends on when he closes the shorts. If he holds them I am fine but it’s also conceivable to buy shorts, publish bad news, see the stock drop and immediately close them.
It's my understanding that "publishing bad news" does not equate to the subject in question being "true", certainly not in today's media climate. Had the OP said something like: "publishing evidence of bad things" then of course that the discussion would have been totally different. And to judge by the discussion in this thread the linked article is not "evidence", is merely "news".
To recapitulate: willingly publishing "bad news" (which you don't have any evidence that they might be true or not) in order to financially gain stuff on a stock exchange should be treated as securities fraud.
The part where he says that he hasn't make everything available because he has fw-ed some information to the police/authorities. Until said police/authorities take the necessary actions (if needed) based on the provided info is best for the parts involved to let said authorities decide if the facts provided are evidence enough.
Also the part where he complains about GE's profit margin being the same as Madoff's, i.e. a guy who was active in a completely different industry, while companies/conglomerates active in the same markets as GE post similar profit margins as GE. This part is fake news pure and simple.