Was David Einhorn a liar or just wrong?

One most interesting stock to watch these days,is Green Mountain Coffee.Curiously,since stock has rebound from low last of 18 this summer to now 45 it has gone unnoticed not much media coverage,this wasn't story when stock was dropping like rock,in fall of 2011 it was over hundred then it drop last summer to under twenty.The main cause seem to be shorting by David Einhorn,plus there was federal investigation,which lead to resignation of the founder and remember watching Bloomberg T.V last summer and mention that Green Mountain Coffee was facing fierce competition and mention Einhorn saw this stock going even lower,indeed much lower the impression was this stock was headed for toilet.But it didn't happen,was Einhorn a liar or just wrong? As far as,I know Einhorn is an honest man,however,he does have something common with Madoff.Einhorn was interest in buying a piece of Met and apparently there had been some speculation about buy a part MET years ago,it does made you think(which usually leads to headaches.)
Perhaps the action in Green Mountain Coffee can explain by a book,written I think in 1841,"Extraordinary Popular Delusions and the Madness of Crowds" written by Charles Mackay.Now I have never read it but understanding is that states people act in packs,or maybe they follow crowd no matter foolish it can be,or in today's language group think.This book was sort of bible,to legacy investor and statesman Bernard Baruch.