I don't think the whole thing comes this idea that Australia's wildlife is mad dangerous or anything, I think it's just that it's MORE dangerous than most other heavily civilized locations. I mean, an explanation of, "Oh, we only get three crocodile attacks a decade" is still worse than living in, I don't know, Russia, where there are no crocodiles.
I mean, let's do a tally:
England:
Almost nothing dangerous as far as I know. Feel free to correct me.
American Southwest:
A few poisonous snakes and arachnids.
American Southeast:
Alligators.
Canada:
Wolves.
South Africa:
Honestly not sure.
India:
Tigers. And Cobras. Okay, that could be fairly bad...
China:
Again, almost nothing as far as I know. As above, feel free to correct.
Russia:
Wovles, I think.
Japan:
Godzilla.
Brazil:
Some poisonous bugs, I believe.
France, Germany, Italy, etc.
Nothing, I think.
Australia:
Crocodiles
Snakes
Dingos
Oh my!
Again, I could be wrong about any of these, so please feel free to correct me. As an ignorant American, I'm always eager to learn.