Why would they need to exile people?

Both Bernard and Helmholtz end up being exiled to an island for not fitting in with the societal norms in Brave New World. Well what I don't get is why would they need to exile anybody in the first place? In Brave New World, you're programmed from conception to follow their norms and to think you've got the best life possible. Whatever class you're put in you're conditioned from the time your in the bottle and throughout your entire life by all sorts of techniques, physical, chemical, subliminal, ect. into thinking your class is the best and so you wouldn't have any desire in the first place to want to switch classes or to rebel against the system. Upper class people are conditioned to believe their classes are the best and by the same token lower class people are conditioned to think their classes are the best. Thus a Gamma for instance would never desire to be in the higher Alpha class because they enjoy the carefree repetitive work that Gammas are conditioned to enjoy by being made less intelligent. Gammas get to just live on in their blissful ignorance and thus they don't want to change classes. So what I don't get is why Bernard and Helmholtz would want to rebel and why Helmholtz helped John throw the Soma out the window. With John its obvious why he would rebel as he did not come from the Brave New World society. He was born not decanted and he was not subject to the conditioning that people from Brave New World would be. Bernard and Helmholtz on the other hand were decanted and conditioned and thus I don't see why they would need to exile them, or why anybody would need to be exiled or punished in any way, if people are simply programmed to not break any rules in the first place.