Heartsinger
You probably noticed that in book 3 the plan for a market that appeals to both dragons and humans also included smuggled goods from off planet. This amazingly does not seem to surprise the dragons which the humans chalk up to not wanting to display their shock and amazement. Look for a different answer in future books, but I don’t want to give anything away.
The market idea is based on the whole cultural exchange from trade that we have seen historically here on earth. When you see a different people’s goods, clothing, foods and interests that are not that different from your own, no one will ever again be able to paint those people as savages or monsters. Once you see a group as people, instead of beasts, you don’t unsee them that way, unless someone deliberately exposes you to “dehumanizing” propaganda and you were so busy thinking about other concerns that you did not notice you were being mind manipulated. Unfortunately that happens…