It does this because "the purpose of the system is what it does"
It ain't no different than the king's men occasionally cutting down a peasant that didn't remove his hat quickly enough when the king rode by. By screwing people on a whim the system sends a "don't cross me, I hold complete power" message which acts as a force multiplier (until it doesn't but Aus isn't there yet).
No, Australia has a very rigid import control system for biosecurity purposes, because the country is currently free of various animal and plant diseases which are endemic in other countries. One infected piece of fruit could, they believe, destroy an industry.
Arguably plutonium guy is being hit with the book precisely to remind everyone who wants to come to Australia that they take import control very, very seriously.
(as well as, you know, the xenophobia that gets involved in any discussion of borders)
A chickend sandwich is probably more dangerous to Australia than a tiny vial of plutonium. Not that I'm saying the 3k fine for what clearly seems like a mistake is reasonable, just that this is even more unreasonable.
It ain't no different than the king's men occasionally cutting down a peasant that didn't remove his hat quickly enough when the king rode by. By screwing people on a whim the system sends a "don't cross me, I hold complete power" message which acts as a force multiplier (until it doesn't but Aus isn't there yet).