You must realize that it is impossible to judge some normative ethical quandary as moral or immoral without having a coherent answer to questions of meta-ethical grounding. If all meta-ethical systems are equally valid, then how can one hope to have an 'objective' answer to a normative ethical question which is informed by a meta-ethic?

The pleasure cube question points towards a deeper issue: is there any way to adjudicate between different meta-ethical claims? If so, how? If not, the question is doomed to lead to a relativistic answer, where the pleasure cube is only bad in one's opinion, but not in reality.