On what grounds can they claim anything? Figured only Bethesda would be able to that and they have no motive to do so.
Could they cause harm if she chose to ignore them?
They have no grounds.
It's a hope that their threats and large numbers demanded will cause the party under attack to settle out of court.
Or a hope that they won't contest it at all and they will basically auto-win the court case because the judge only hears their story.
However, if they win they instantly become massive targets for Zenimax laywers.
This happens because there is no "trolling" penalty beyond judges being more skeptical of cases your company raises.
The legal system needs some kind of massive, company-ruining fine for cases where there is no factual basis for the claim and the case is designed just to scare someone into submission.
Something automatic. A process the judge can start at his or her discretion without costing the victim anything for a separate fraud case.