The best response to the complaint that an all loving God wouldn't allow for something like the Doctrine of Hell is provided (as always it seems) by C.S. Lewis. When talking about simply unrepentatntly bad people he responds:
'What are you asking God to do? To wipe out their past sins and, at all costs, to give them a fresh start, smoothing every difficulty and offering every miraculous help? But he has done so, on Calvary. To forgive them? They will not be forgiven. To leave them alone? Alas, I am afraid that is what He does."