While I'm 100% for vaccinating children, this is a total violation of the freedom of parents. But then again, I'm also against things like seat belt laws because why the forget should you have to wear a seat belt if you don't want to? It's your own life you're endangering.
Ehhh not wearing seatbelts can present other risks. I get what you're saying though. I.e. you could get ejected from the vehicle and land in moving traffic causing a gruesome danger to other motorists. Being ejected from the vehicle usually means busting out the windshield as well, presenting a safety hazard with broken glass.
It could be compared to Self Delete too, which is usually intercepted by police and psychological examiners in the case of a failed attempt. Even though it is your life that is ending, you will likely cause insurmountable grief to friends and family regardless of whether you think you will or not. A lot of money will also be spent on investigations and someone will also have to eventually clean up the mess you left.
But I agree that certain things (including this Australian law) should have the freedom option vaccinating children. Yes, it is not smart and quite irresponsible to prevent them from receiving any vaccinations, but most people get at least some of them.