I'll provide an answer against the statement "The fast-food industry can give valuable work experience to teenagers.”
The fast-food industry is not at all concerned with the value the experience of working in it will add to someone's life. As was stated in the text, they hire teenagers "because they are less expensive to hire than adults, but also because their youthful inexperience makes them easier to control." The experience those workers will acquire from that job is limited, probably even useless in other areas. A McDonald's employee does not learn how to cook - they can't leave McDonald's to suddenly work at a regular restaurant. They have machines beeping all around them, letting them know when the food is supposed to be ready.
I agree that fast-food jobs can give work experience to teenagers. At the same time, I wonder how valuable this work experience is. In Fast Food Nation, Schlosser mentions that teenagers with these jobs are not paid well and often do not learn new skills. In addition, time on the job can take away from their focus on school.