Well, there's the utter lack of an attempt at diplomacy. The Warrior of Light and Scions attempted to broker peace between the Ishgardians and Dravanians. They failed, multiple times - but persisted regardless. Even after meeting reasonable Garleans such as Regula they failed to even acknowledge the possibility of peace - and if they continue to avoid trying to secure it then they're simply massive hypocrites. They're now supporting destablising territory that isn't theirs to reclaim - causing fear and panic. I hope the Scions and their allies pay dearly in blood for any Garleans who lose their children, lovers or friends in rebellions incited in otherwise peaceful territory. We already know that not every part of the Empire is a cesspit - some territories are virtually unchanged by Garlean rule. We've heard it but we'll likely see it for ourselves in due time.
Yet the longer the Warrior of Light and his allies fail to attempt diplomacy, the more needless bloodshed there will be. I suspect that you'll counter with 'but the Garleans aren't interested' but even if that turns out to be true (which is unlikely, given the mixed opinions on things like the Meteor Project) it doesn't change the simple fact that the Warrior of Light and his allies refused to take 'no' for an answer when it came to peace between the Dravanians and the Ishgardians.
It's not like there isn't a mutual goal in regards to putting an end to the Primal/Eikon threat once and for all, either. Here's hoping we'll see the Garlean Consulate in Kugane used to discuss potential diplomacy with someone along the lines of Regula, Reeve, Larsa or Drace. Ideally someone who will just as readily call out the Eorzeans for their dubious elements just as quickly as calling out Garlemald's own.