If the only way to turn the situation described in BNW (ignoring the savages) into an eudaimonic utopia was by torturing the whole population for a couple of years first, would you think it was the moral thing to do?

The Brave New World setting requires that the majority of the population undergo intentional directed mental retardation and cultural disability, among with other matters+. So, yeah, even assuming massive discounts on future suffering and a very low value for the "intelligent diverse" part of "intelligent diverse lives". That the folk brain-damaged into slaves /like/ being slaves doesn't forgive the brain damage or the slavery.

• Huxley also sets the world up so that several basic and emotional drives are tabooed, vast amounts of labor is wasted making things by hand, large portions of media space is off-limits for the normal folk, and implies that there's not really meaningful consent for sex. Soma's honestly the least of the problems for the BNW setting.