Why is anyone paying any attention to anything said or done by Barghouti, a convicted murderer serving five life sentences? Who cares what he demands? If he chooses to starve himself, so be it. If other prisoners decide to imitate him, that is their choice. No one else is responsible for their actions but themselves.
All Muslims could stand to miss a few meals, but if this "hunger strike" is anything like the Ramadan "fast", there gonna be fatter afterward than they were before.
I agree that incarceration must be difficult and unpleasant. However, I imagine incarceration in Israel must be like a vacation spa compared to prison conditions in Egypt, Iran, Lebanon, Syria, Iraq, Yemen, Algeria, Tunisia, Turkey, or even Saudi Arabia. Prisoner demands and threats of hunger strikes are like children demanding they get their way or they'll hold their breath.