I assure you tribal people have had their fair share of events and parties where restrictions of various kinds apply. There’s a place for everything and who’s in and who’s outsider for various matters depends on that matter.
This year’s Liberation Day was very open, with the Games open to all indie capsuleer, and our public events the same. That does not mean all Minmatar events are the same. Family, clan, tribe, tribal allies, all allies, all non-hostiles, everyone - these are all valid target audiences for Matari events.
There’s nothing particularly Amarrian in Arsia choosing not to invite her enemies to her anniversary party.