Other than hosting child pornography I thought that you couldn't hold the hosting company libel?
I think the issue is that the bank claimed the web site was unresponsive to requests to remedy the matter outside of court.
Some will say "but they didn't identify who they were, or what they wanted." I read the email exchange and all I see is wikileaks playing a cat-and-mouse game. The end result is that that they should have put the bank's attorney in touch with an attorney (any attorney).