Answer:
Because they saw the European settlement as an invasion that created a conflict between the two peoples.
Step-by-step explanation:
A belligerent action is one that promotes a war, a conflict and a dispute over something. The aborigines saw the European settlements, during the colonization of australia, as a belligerent action, because they saw the settlement as a dispute for the territory. For them, this dispute would be resolved through direct conflict, generating war between peoples, for the domination of Australian lands.