It was stated officially that the Nagas hated the humans because of the Jade Wind.
It is no doubt that the Jade Wind killed most of the Nagas at the Jade Sea area. The Nagas' there should indeed hate the humans. They changed their whole culture from peaceful shamans into blood lusted warriors.
However the ocean is huge and Nagas elsewhere survived. In fact the Jade Wind would barely effected them. The Nagas in Shing Jea Island is one such example. There is no indication that the Jade Wind effected them in any way. Their food supply and livelihood should all be in tact. So why are they hostile to the humans? Why would they changed their culture to barbarians when the incident didn't effect them?