I think we're pointing this out to you because it would need to be looked at again: that I have the right to refuse to investigate complaints, and only in certain cases could the individual go to court.
There's something called judicial review in law, which means that when I exercise my discretion unwisely, unreasonably, or incorrectly, depending on the standard—and that's standard for all decision-making bodies—the courts would catch any errors I made in using my discretion and not investigating certain cases.