I just don't understand how the protection of rights is relevant to the question. Isn't it two different things? Like isn't the question asking about the action/role of the high court??
Oh, okay, that makes sense.
Okay, so you understand the idea that the HCA can invalidate laws that are outside a power of the Cwlth Plt? (and can do the same for the states)
The next step is understanding how/why something could be outside the power of a parliament. One way something can be outside the power of the Cwlth is if it's a residual power and not listed in the Constitution. But another way is if it's a restriction on their power - eg s92 or s80 or even the principle of representative government. A restriction is just an area on which the Const says the Plt cannot make law They key is understanding that some restrictions are just called 'rights'. Not all get the name, but some do (and it's a bit arbitrary).
So, therefore, SOMETIMES when the HCA invalidates a law it won't be relevant to rights - eg if it was just a law on residual powers. But SOMETIMES it will - eg if it was a law on a restriction that has been classified a right, such as s116 or the freedom of political communication.