Just look at the ongoing stoush between the Turnbull government and the Catholic school system. It notched up another level of tension recently when news broke that Catholic Education Melbourne is being investigated by the Australian Charities and Not-For Profits Commission, because of its advocacy for Labor’s school funding policy during the by-election in the Melbourne electorate of Batman.

It escalated quickly, with Bill Shorten describing the investigation as “un-Australian” and Tony Abbott saying it was “picking on the Catholic Church.” But what exactly is all the fuss about?

Essentially, federal government funding per student is going up significantly for all school sectors (government, Catholic and independent), but this increase isn’t as much as teacher unions and Catholic schools would like. The school funding formula is skewed by historical and statistical anomalies. A recent report by the National School Resourcing Board found that it tends to disadvantage Catholic schools compared to independent schools.

This debate over details will continue, but the passion it has ignited shows the importance of federal funding for Catholic and independent schools. Which raises the broader question: why does the government fund non-government schools at all?

Ultimately, because it saves taxpayer money and gives parents more choice over the education of their children.

The government funding received by most non-government schools allows them to keep fees low enough so that middle-income and low-income parents can generally afford them. Without any government funding, Catholic and independent schools could only be for the very rich.

Parents directly contributing to the cost of their children’s schooling means that the government doesn’t have to foot the entire bill. The existence of non-government schools has been estimated to save taxpayers between $2 billion and $9 billion per year. More importantly, non-government schools receiving financial assistance means parents are empowered with more school choice.

Australia has a relatively high proportion of students in non-government schools at 34 per cent – more than twice as much as the international OECD average of 16 per cent. School choice is firmly embedded in our education system.

While the majority of parents end up choosing the local government school, at the end of the day, parents generally know what’s best for their own children.

Parents want to send their children to a school that reflects their values, or at the very least does not undermine them.

Government schools are not values-neutral or the default option any more than religious schools.

For example, controversial government programs like Safe Schools are strongly opposed by many parents. Sometimes, parents opt for a non-government school for academic reasons (although there are many high-achieving government schools) or for the extra-curricular opportunities.

Of course, for many parents – such as in some rural and remote areas – there is, unfortunately, limited or non-existent school choice. That’s why it’s important to ensure there is a high-quality government school system across the entire country. But this is not incompatible with also supporting a strong and diverse non-government school sector that takes financial pressure off the government system.

Parents need to be provided with the information necessary to make an informed school choice.

The MySchool website – an initiative of Julia Gillard when she was education minister – provides easy access to clear information about schools, including their academic performance on NAPLAN tests.

MySchool has been under attack recently, with claims that publishing school NAPLAN results puts too much pressure on teachers and students. But there have been no rigorous studies of how parents use MySchool data, and no substantial evidence to suggest MySchool has any negative effect on schools or students.

It is far better for parents to have access to objective NAPLAN data in their decision making, rather than having to rely solely on other factors like school reputation, school uniforms and school websites.

Academic achievement is just one of the many factors parents use in choosing a school, and it’s patronising to suggest parents aren’t capable of understanding the limitations of NAPLAN data. Transparency about school NAPLAN results helps keep the education system accountable to parents and taxpayers.

Parents are primarily responsible for the education of their children, not the government. They should be supported regardless of which school they choose.