On the side of the State:
The state has a vested interest in maintaining good order in prisons. Prisoners who are allowed to dictate their own behavior not only represent a threat to prison authority, but encourage others to do so as well.
The state has a vested interest in ensuring that prisoners do not use the circumstances of their imprisonment (such as a hunger strike) to foment unrest in society outside the prison. Such demonstrations tend to attract media attention, which in turn tends to attract potential sympathizers.
The state also has a legal obligation to provide basic health care to inmates; obviously if a prisoner maintains a hunger strike long enough, they risk death or serious injury. The state typically take steps to protect inmates from being able to injure themselves or others when such conditions exist, including isolation cells, restraints, or whatever else is reasonably deemed necessary.
On the side of the Prisoner:
Prisoners have severely restricted rights, but in general they are allowed to pursue legal avenues to gaining attention from others. That might include letter writing, filing petitions, writs, and appeals, or calling others on the phone in whatever circumstances they are allowed to do so.
Hunger strikes are among the few 'force multipliers' that are essentially non-violent and which tend to attract media attention to the situation the prisoner wishes brought to the public attention.
In other words, I understand why prisoners go on hunger strikes. It's a sophisticated form of protest that is designed to get others to pay attention to them or their message, whatever it might be. However, the State has an overriding interest in not allowing such behavior. I support the force-feeding of hunger-striking inmates if it becomes necessary.
