The community has chosen to separate itself from human emotions of all kinds.  The pain is centered on one person, the Receiver of Memory, in order that the others do not have to feel anything.  Notice that the Receiver usually seems to just accept the pain, other than cases like Rosemary, and so the system perpetuates.

I think that this is because it would destroy the whole system of sameness and lack of emotions.  If everyone were exposed to all of the things Jonas felt, they would all have those emotions and would be unable to have the sameness that keeps their society so stable.