Rightly or wrongly, it has become a culture war issue where support of Israel is associated with centre to right positions whilst opposition is associated with left positions (not saying it has to be either/or, that's just how it's commonly framed). A lot of Australia's media ecosystem is either centre or right leaning, which means they will inevitably push the Israeli narrative harder. Additionally, the pro-Israel lobby is super active and well financed and rabidly goes after any journalist or publication that doesn't adhere to this default framing of current events. In places like the ABC and the BBC, I think both factors influence the reporting which is why you see a subtle bias despite those organisations claiming a position of balance.