Accepting that philosophy is about the world also eliminates the idea that philosophy is to uncover the correct definitions for words like “justice”. The question “what is justice?” has no right answer outside of the context of a philosophical theory... Justice can be defined however we wish in the context of a philosophical theory; the theory is not judged by how well it defines justice by how well it describes the world. Of course it is preferable to define justice in a way that fits with our intuitive usage for the sake of clarity, but it isn’t necessary. And this saves us from the impossible task of trying to find the “right” definitions.
Well, certainly the question what is 'justice'? is uninteresting. 'Justice' is a word. There, that was easy. But the question what is justice? remains of interest. (Sure, you could stipulate that 'justice' is henceforth to mean zebra. But that wouldn't make the ethical question any more black and white.)
See Is Normativity Just Semantics? (The short answer is: no.)
His response? Deletion.
I guess I won't be commenting there again any time soon.