tl;dr: We on the left need to take concerns about immigration and about excessive societal liberalism serious again, or we will become the ideology of the white upper middle class and not of main street. You insinuating that these voters are are all coldhearted, evil or intolerant or whatever is exactly what has gotten us in this mess.
I'm a proponent of taking these concerns more seriously in the contexts of most developed countries, but in the case of Australia the Overton window on immigration/nationalism/national identity-type issues strikes me as being so far to the right already that surely there has to be some sort of limit. Again, I stand corrected about the extent to which that contributed to this result.
I dunno, people forget that it often has been leftist governments that have put restrictive laws on immigration in place; and attempts to play that game have often seemed to have backfired, seeing as you can't really outdo the populist right on the issue, but at the same time talking about immigration like it is a problem merely serves to validate the idea that it is one.
I mean, it's one thing to respond to people's concerns or whatever, but what the left does well; and what it is supposed to be about; is fighting for equality and sticking up for the vulnerable and the less powerful. So if you go and undermine your own values (especially in an era where having values seems increasingly important in electoral politics) just to fulfil some narrative about how "white working class" voters are all apparently xenophobic; I don't think that ends well to be honest.
probably a point for a different thread though.