Tihan said their fund will already be pursuing legal action against the consultancy. And the consultancy aren't the owners and don't have assets anyway.
Legal action is needed against Tihan and "wendon" (the mysterious owner, Tihan is supposedly a middle-man according to patrick). Both the venture capital fund and the bitcoinica legal entity in new zealand should be the focus, ultimately it was their responsibility which they psssed on to the consultancy. And, they actually have the assets to cover the losses (they also invested $500k in coinLabs).
It's actually not clear that $500,000 investment in CoinLab by Draper Associates and others intersects with Bitcoinica in any way. In fact, there's a post somewhere (I'll try to find it) which says that Bitcoinica approached CoinLab for help after the Linode hack and they were unable to assist, which suggests that the investment group which is the limited partner in Bitcoinica is another group for which Tihan finds investments (this isn't at all uncommon in the world of VC).
While in the US you can "sue anyone for anything", that's not universally true elsewhere. It's absolutely vital that if people want to litigate this they consult experienced litigation lawyers in the appropriate jurisdictions. It's not simply a matter of "pick a defendant, any defendant". It's also important to take into account that costs awards in some countries are only a proportion of the actual costs spent on litigation - you can still be out of pocket financially even if you prevail in court. The cost of suing multiple defendants across multiple jurisdictions will not be small and the process will not be a rapid one.
They still exist, merely their possessors are illegitimate. This means that it is possible to repossess them. Until they are returned, the rights of the depositors are being violated, even though it is unclear who is to what extent responsible for it. Even if I personally did not care whether my money is returned, I still want to live in a world where property rights are respected. This requires enforcement.
I think that one of the reasons people have been willing to write off losses in the past is a desire to avoid their transactions coming under legal scrutiny. Making a legally enforceable claim involves identifying yourself, and some people would rather forfeit their funds than do that.