As far as I can see, the court is not doing here anything else than interpreting the law. Literally, the whole ruling is explaining pieces of the law step by step.

> The objects of the EPBC Act include providing for the protection of the environment, especially those aspects of the environment that are matters of “national environmental significance”: s 3(1)(a). Section 3(1)(b) states that a further object is the promotion of “ecologically sustainable development” through the conservation and “ecologically sustainable use” of natural resources.

> The following principles are principles of ecologically sustainable development:

> (c) the principle of inter-generational equity—that the present generation should ensure that the health, diversity and productivity of the environment is maintained or enhanced for the benefit of future generations;

The purpose of various government bodies are not simply to all be equal tools for citizen desires. At least in the United States, each branch is "co-equal," and "checked and balanced." This is on purpose. A particular branch has the power to perform certain activities, while other branches don't.

> at a citizen's disposal

sorry but how are courts at my disposal?

Prosecutors and regulators have discretion to ignore any harms you suffer. But you still have the right to file a lawsuit.

... as in, you have them available to you?

No, courts aren't there to bypass the democratic process when the policy of the country doesn't fit your own politics. They are not elected, are usually pretty much unaccountable. They should not issue laws or make policy.