hate the occupy wall street folks is simple: they have bypassed the old left leadership. The old left is not making any money off this, is not leading it, so they hate it because it challenges them.
The old left exists to bring in money and keep paying themselves. This is as true of union leadership as it is of the majority of environmental organizations. The leadership of almost all of these organizations is deeply corrupt. All they care about is whether they can fundraise off of something. If they can’t, they despise it. They will, and do, regularly sell out of the interests of their own supposed constituents, in order to make their personal lives easier, to get richer, and to keep hobnobbing with important people.
Movements which bypass the old left, like Occupy Wall Wall Street or Wikileaks, or Anonymous, are MORE of a threat to the old left leadership than the right wing, the Tea Party or the Republicans. Those forces are all good for the old left, they use fear of them to drive donations, and to convince their followers to vote Democratic, for which they are then rewarded with access, pats on the back and small amounts of money. A genuine left wing alternative to the old left leadership is an existential threat to them, and thus they attack them.