Many individuals are graduating from modern nursing programs
, while still sorely lacking in very basic nursing skills such as toileting, bed baths, transfers, perineal care, ADL assistance, etc. In addition, many new nurses are unreasonably disgusted and dismayed at the mere thought, smell, and sight of bodily substances such as feces, urine, sputum, saliva, blood, and sweat. Some of these people were seriously under the impression that they didn't have to deal with the "dirty stuff."
While not necessary, I tend to think that earning a CNA certification is a good prerequisite for nursing school, because it exposes the student to basic skills that should be fundamental. In addition, it exposes students to the "dirty stuff," hopefully enabling them to feel more comfortable around it later on down the line.
There's nothing worse than a nurse who believes (s)he is too good to empty a urine bag.