Many youngsters go through the process of interviews etc but have no intention of taking a job many ruin the interview or do not accept the job giving phony reasons.
In Britain you have to prove you are looking for a job to get benefit - I would assume it is the same in the US.
Many youngsters go into the job centre daily have to sign on once a week at a certain time and show evidence of trying for work and then spend the rest of the day hanging out with their mates.
I would suspect of the percentage you quote there is a far number that are similar to this.
Unfortunately the few give the rest a bad name but it still does not alter the fact that often to get youngsters to work from 16 - 20 it is a struggle for parents.
The official unemployment survey is based on those folks who have applied for unemployment benefits or who are registered at unemployment offices for job openings.