if I understand correctly, it's actually because she is. it explains that in order for a civil case to be under the jurisdiction of a federal court (and a civil case must be what she's attempting, since she doesn't cite any federal law to allege that the defendants have broken it), none of the plaintiffs can be citizens of the same state as any of the defendants. otherwise, presumably, it would fall under the jurisdiction of whichever state both parties are citizens of. so because both she and some gay people are Nebraskans, the case would have to be handled by a Nebraska state court, not a federal court