At present in NSW, scripture classes are held in public schools (despite Australia's secularism) and where children choose not to attend, they are not allowed to be taught anything, so children have to sit outside the classroom, or sit outside the headmasters office or sit in the library.
A trial of ethics classes is being introduced so that these children can learn something useful instead of sitting outside. However, the churches are using all their lobbying power to stop the introduction of the trial arguing they may take students from scripture classes. It appears, for the churches, that this is a worse alternative than children having to sit outside the headmaster's office whilst scripture classes take place.
Being against the teaching of ethics due to it potentially taking children from scripture classes and thus ensuring children continue to sit outside the headmaster's office would appear to be unethical in itself.