Moral skepticism is not particularly impressive as it's the simplest hypothesis. Certainly, it seems extremely hard to square moral realism with our immensely successful scientific picture of a material universe.

The problem is that we still must choose how to act. Without a morality, all we can say is that we prefer to act in some arbitrary way, much as we might arbitrarily prefer one food to another. And...that's it. We can make no criticism whatsoever about the actions of others, not even that they should act rationally. We cannot say that striving for truth is any better than killing babies (or following a religion?) anymore than we can say green is a better color than red.

At best we can make empirical statements of the form "A person should act in such-and-such manner in order to achieve some outcome".

Some people are prepared to bite this bullet. Yet most who say they do continue to behave as if they believed their actions were more than arbitrary preferences.