In my opinion, the problem is we spent too little time with the dragons considering our interactions are limited to a bit at Anyx Trine, and a bit after that. We've got no understanding of why they feel this way, and yet the story spends so much time painting even conservative Ishgardians like the barmaid that drugged us in a sympathetic light. The story and writing with the dragons lacked quality and that's the big issue, while we got time to talk to the lower class and higher class of Ishgard, buddy buddying with Aymeric and other Elezen forever the dragons lacked that same deal. Even Hraesvelgr had feelings of tiring towards the war, even if he hates to admit it or show signs that don't seem arrogant to himself, his dialogue before Sohr Kahl seems to indicate so. Midgardsormr's words just pushed him to give out a trail, to test us as basically any other character in the story has done before, and all things considered (Dragons giving plenty of respect to their family), Hraesvelgr changing his mind a bit after his father's words is hardly bizarre. I think you'd being a bit too harsh on the dragons (Or rather the story failed to try much at all to making the dragons sympathetic when it's not hard to do so). Dragon's have a haughty way of speaking. Similar.. Look at the nobles of Ishgard or Ul'dah, beings of power mean the same way and I don't think there was any ill will to him calling Aymeric arrogant, it's just how they spoke. It also should be said that I'm not sure on the Japanese dialogue, which from what I've read concerning Midgardsormr, often writes him a whole lot less arrogant and I wouldn't be surprised if it was similar with Hraesvelgr