Well most of them (nearly all) can’t help but ape the moral standards around them, but they’ll argue the self-destructive nihilism as it is convenient to win an argument, even while living in and tacitly demanding society act in some “proper” manner.
It is why it is such a funny and childish ideology, because many of them at least argue that they sincerely believe that morality is entirely a shifting subjective construct, but none of them have the courage to take that concept to its conclusion.