I don't need to have taken a debate class to know that there isn't a visible reason in that post.
I'm going to guess that you're a fan of some type of moral nonrealism (as in, morality isn't a law that we can find somewhere in the universe).
In which case, you still can talk about how humans have become deluded enough to believe that morality exists, or why do some people adopt some moral systems rather than others or, how we can implement specific branches of morality that people believe in etc. etc. etc. Those are all complex questions yes, and they may not have good answers, but surely there has to be a plan of attack on how to answer those questions too, right?
Or your objection could be to the "well even if there is a solution, we can't expect there to be a consensus!". But then you'd have to answer why for everything we consider "solved" that we typically do expect consistency among experts or the form of the solution. You don't build a bridge if the calculations come out completely different every single time, why should it be different for any other field, unless you feel like the field is "unsolvable" in which case why toss people uselessly onto an unsolvable problem?
Perhaps ethics is a uniquely bad example, pick your poison: Nature of the universe, cognition, epistemology, theology, human behavior. Either way, the criterion remains the same: How the hell do we know if philosophy is doing anything at all?
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You're messing with me! You're messing with me, aren't you!?
You're making fun of me, aren't you!? Aren't you!? You definitely are! I'll murder you!