Setting aside this specific situation. Let's say you run a prison, and an inmate goes on a "hunger strike" for a reason that's important to them. What should the prison operators do? Force feed the inmate, negotiate, give into their demands, or let them die? Let's say you try to negotiate, but the inmate is making unreasonable demands or you are not willing to meet their demands, then what?
To everyone saying to let them die, then where is the punishment? Most terrorists would rather and, in fact, intend to die during their attacks. If you let them die, not only are you giving them what they want, but then there is no deterrent to carrying out suicide missions.
The deterrent premise is as old as at least the Inquisition (12th century) and has worked out quite well to reduce crime and recidivism rates in the world to nigh zero levels in the centuries since... /s