There are wholesale numbers of fringe parties who will never form a government. To lose the election these are all that is required for the major parties:

• argue that global warming/climate change is a hoax
• argue that covid is almost a non-existent problem

Suppose Scott Morrison thinks exactly that. He cannot say any of it since the Coalition would end up losing in a massive landslide.

There are other issues too, but those alone would do it.