Isn't Eccieleaks protected from prosecution because it is a parody site?

No.

First, being a parody site does not protect anyone from being sued for defamation.
Second, many reasonable legal scholars would not see what Eccieleaks does as parody.
Third, from a practical point-of-view, the parody defense has involved public servants and "famous" people, not the regular people that Eccieleaks targets.

I seriously doubt that one could convince a jury that creating a fake conversation between two children - a brother and a sister - where they argue about him sodomizing her is valid parody. And then to deliberately create links on the Internet to encourage those children and the friends of those children to look at this fake conversation?

I think that the court would need extra bailiffs to keep the jury from assaulting the leaker defendants.