I find that this is the best approach to moral questions: define them such that the distinctively moral terms are “cashed out” in non-moral terms.
After all, morality as humans practice it came from something that preceded it, and it has been successful for a reason. What is that reason? What function does it serve? In other words, what makes it adaptive? In other words, why are moral creatures more fit than the non-moral?
This post does this. It asks “What is the adaptive purpose of free speech?”. It does not ask “What does common sense say free speech is for?” nor does it ask “How can we define free speech in order to benefit that group which we think is most victimized?”. No, it starts from first principles, as a philosopher or scientist should.
It seems strange to modern minds that the purpose of a thing should be its adaptive function, but this is they only way to cash out moral terms in a more fundamental set of terms and thus “ground” them. Remember, if you want to define something, you must define in terms of that which is better known, not in terms of the less known.