Complex sentence: Over the years, dingo trappers gained a kind of prestige for their work, primarily when they managed to kill dingoes that were especially hard to catch, so dingoes were associated with thieves, vagabonds, bushrangers, and parliamentary opponents.
Split into simpler sentences: Over the years, dingo trappers gained some prestige for their work, especially when they managed to kill hard to catch dingoes. Dingoes were associated with thieves, vagabonds, bushrangers, and parliamentary opponents.