Answer:
Although it is true that "individuals with only high school diplomas (are) significantly less likely to get jobs inmmediately after graduation...," the fact remains that allowing recently graduated high-school students into the workforce presents benefits not just for the student, but also for the workforce, as it is shown that hands-on experience helps the student mature and may also make him even more capable of making better decisions in future regarding profession and future job choices.
In fact, even though students should be encouraged to go all the way in their educational pathway, it is undeniable that hands-on experience after high school, experiencing what it is like to live in the adult world, through work, can mature a person, make him more responsible for his choices, and make him better aware of the decisions he/she needs to make to improve his life. Working is also another form of educational experience, and if managed correctly, and without encouraging students to leave their formal education aside in favor of menial jobs, it could lead to more secure, and more responsible college students and professionals in future.