I don't think it's that as much as it's the nature of AvP as compared to the nature of Australia.
We Aussies live in a country where spiders the size of cars live in subways and the only thing bringing rain is the occasional rainsong from whichever Aboriginal shaman happens to be nearest. So we don't really feel like the Aliens or Predators are scary - they're like old friends that we like to run over with trains and discriminate against on the basis of a dark, racist, white supremacy past. AvP isn't so much AvP to us as it is 'Australia: The Game'.
It's almost national identity, it is.