In part due to under funding and under staffed facilities. True, those incarcerated are there to do their time, pay their debt to society. And that doesn't mean each cell should be a hotel room with room service. But the cries that reach those who are listening, are horrid ones. Besides this, sometimes the sewers overflow, leaving a big health hazard on whole ranges.
Rodents can and do come up via the wc s.
There are alarm buttons, should there be an emergency. However, these buttons are disabled from time to time, causing people to die from heart attacks or suicides, while the neighbouring cell's inhabitant can do nothing but hear the other die. Life becomes nothing but sheer survival. For those who do get released after a period of time, this frame of mind means everything but rehabilitation. So these people are sent out into a world in which they fend for themselves as in prison, with the feeling society owed them.