It is fairly simple. The majority of bears on this forum fall into several categories (in no particular order):

1) sold and want to buy back lower and increase stash (reasonable gamble in a bear market)
2) sold lower and now the price has moved up against them (screeching about 50$ coins, it's going to double digits!, praying for price drops)
3) short from above this price (in the money, vocal because the market isn't dropping further as expected)
4) short from below this price (ho ho ho, thought it would go to zero because 'line on a chart')
5) troll (see NLC, or the alts.)
6) permabear (Edward50, Nagle - thought bitcoins were overpriced at 2$, now desperate for bitcoin to fail to validate their enormous life mistake)