"Adventurer, we are truly grateful that you've come to slay the giant dragon, that Archis is just too evil."
"Could you explain in detail, please? To my knowledge, the Golden Giant Dragon is supposed to be a dragon of justice."
This is common knowledge. Giant dragons come in all varieties, and the Golden Giant Dragon, being among the top breeds of giant dragons, also leads the Justice Giant Dragons. Generally, they maintain good relations with all the major races.
It's even common for individuals to gain the approval of a Golden Dragon through their deeds, and then become a Dragon Knight.
It is the highest honor for a knight. Although one often hears about it, in reality, few actually achieve it.
Moreover, Golden Giant Dragons are very united. If anyone attacks one of their dragons, these creatures will band together to retaliate. Numerous and powerful as they are, this is generally why people dare not provoke them.