According to this article detailing a recent federal lawsuit that has been filed, "Inmates, according to the complaint, “live in a constant danger of being murdered, stabbed, or raped that is so profound that the federal government has sued Alabama for inflicting cruel and unusual punishment, and if they refuse to work, the State punishes them even more.”

Further on, it continues, “The complaint alleged that in addition to subjecting inmates to harsh conditions and an ever-looming threat of solitary confinement, the work programs created an irreconcilable reality: incarcerated individuals were routinely denied parole on grounds that confinement was necessary for public safety while those same individuals worked regularly at fast-food restaurants and other local businesses without supervision.”

They can have their sentences effectively be longer because they refuse to work. You know how people get their sentences shortened due to “good behavior”? Refusing to work is seen as not having good behavior.