Certainly.
I don't find it shocking or dismaying. I actually do understand that morality and virtue are concepts created and defined by humans.
Plus, being a good Cartesian, I'll entertain a criticism of that view, namely, how do we know that this is the right concept?
Possible answers to his have already been given in the history of our books. All of them seen to follow something that Aristotle says about virtue. He says that ethics is living in accordance with a principle. He points out that this is more than simply material behavior since it involves choice. If we deny choice, that changes the rules and we have to start over and ask again, what is your understanding of virtue.
And any principle will do, in a pinch? It seems not, so then the next question is, which principles, and why those? We can certainly imagine an ethical system constructed around the principle that all you peons do and say should be for my personal benefit, but somehow I suspect that some will object.
Perhaps, instead, we should find a set of principles for which there is some broad agreement. But if we do that, what is the need for a third party to dictate said principles to us?