So about that new dungeon

[Alleo]

She was the one under attack. She didn't strike first.

Lets not forget that the others had tried to talk to them and tried to make peace to them only to suffer attacks and get important food stolen. They were the aggressors. If they should have hated someone then it should have been us and Bismark but seemingly they already hated people before that and this made it only worse. They were outright breeding to get to war which would have let to the death of the Ondo and other people.

They attack us right away, while they had the chance to talk to us.

Through acts of piracy, yes. Though the Scions already turn a blind eye to acts of piracy conducted by the pirates occupying The Ruby Sea. They were never interested in finding a peaceful solution - they just wanted to get to their destination as quickly as possible and saw the conflict as an inconvenience in the fact of their goals.

When did the pirates at the Ruby Sea ever go out of their way and say that they will mass murder villages? The pirates were willing to talk and thus the scions used that to reach their goal. These were not ready to talk and are an active danger to the Ondo (who are the ones that beg us to take care of them) and only after they heard that did we agree to do something but Alphinaud and others highly dislike it and wished for a diplomatic way which was sadly never on the table.