Our laws are of two types:
* statute law - these are the laws written by the government
* common law - these are the laws that are created by court decisions
The idea of common law is that the statute law can't possibly take into account every possible circumstance and combination of circumstances that could be possible, so frequently the Courts have to make a decision where one law would suggest they act one way, and another law suggests they should act another. They have to look at all the various laws - planning laws, property law, tenancy laws, discrimination laws, and possibly even Constitutional issues etc. - and decide which should prevail in a particular situation.
Once a Court's made a decision, every other Court at the same or a lower level is obliged to interpret
the same set of facts in the same way. (That's what's known as "setting a precedent".)
So in Queensland, for example, we have the Magistrates' Court, the District Courts, and the Supreme Court (from lowest to highest).
If the Magistrates' Court makes a decision that interprets something in a certain way, all subsequent Magistrates' Court decisions on the same issue have to do it the same way.
But if it's appealed to a higher Court, then the District Court could decide to "over-rule" the interpretation of the lower court, and then the District Court's interpretation would prevail over all future District Court and Magistrates Court decisions. The District Court's decision could be over-ruled later by the Supreme Court, and then that would become the new binding precedent.
It sounds like what's happened is that somewhere along the line, a Court has interpreted the planning laws in a way that Council and State Government don't like, limiting their ability to take action against people who are acting contrary to what they want - like you.
There's no point them going after rogue landlords, if there's been a decision which shows that if you dug your heels in and they had to take you to Court, they'd lose.
Things have evidently gotten bad enough that the Government's decided to appeal a decision to a higher court, to try and get a new precedent set, so that they can take firmer action and know that the Courts will support it.
I am not a lawyer (not that I like to brag badoom tish) and this is not legal advice, but a likely imperfect summary of how these situations arise.