According to Kant, the Moral Law is called "The Categorical Imperative" because it is a universal law—a special duty—that applies to all persons, regardless of their inclinations and desires.
Imperative means that it has to be obeyed - so based on his theory, one might assume that it is of absolute importance to follow these moral laws in order to be a valuable member of the society. Regardless of what you think is right or wrong, you have to follow the moral laws that the society made or else you will be an outcast.