The Org would have a large file on responses to threats to sue for d'f and would provide the cong' concerned with information to handle most situations. I think defamation would be hard to prove and would depend on what the law of the land is in your country.
I have thought though that instead of suing for defamation and a like, take it a step backwards, in that your membership in the Borg in the first place was based on deception and misrepresentation. Had the elders/org been completely open and not only offered information in relation to the Org and its teachings (all its teachings, old and new) on any subject you might want to know about, but also provided you with all history of the organisation and demonstrated without restraint the consequences of various actions, your decision to join may have been different. Had the Borg disclosed all information to potential members, including failed prophesy, double standards for different parts of the world, sloppy organisational administration etc etc again your decision to join might have been different.
Given that once you start studying and learn that to read information about the Borg from an external source is not allowed, the onus is place even more strongly on the Borg to provide it themselves, all of it, or else how can a completely informed decision be made by the potential member. Now not only is the Borg responsible for selective information being made available to the student, so to are the elders, personally. They are individually responsible as well! They would have such information in their possession and choose not to disclose it to students. So maybe not only could the Borg be responsible for and guilty of deception and misrepresentation and even gaining membership under false pretences, so too are the elders concerned personally.
Just a thought!