Prior to the gold rush providing a massive boost to the colony’s population, the working class was composed mainly of ex-convict elements or underprivileged immigrants who had come out to Australia under assisted passage.
These were people accustomed to oppression from establishment elements and for many of them the bushrangers were heroes giving voice to the powerlessness of the working classes.
By staying close to their roots in country they knew like the back of their hand, the bushrangers were hence able to rely on the support of some elements of the population.
This did not mean protection for the poor however. They were robbed as freely as anyone else. Just that the bushrangers definitely knew who their friends were, and you surely didn’t want to become one of their enemies.