Because a probation officer is a interesting job, and many teens and young adults are committing crimes worthy of probation. Probation makes it so that, either A) you don't have to serve time or B) to keep you out of trouble after serving time. Its used so extensively, because it shows good results, and often always showing up with positive reply.
The main reason why mass media is more effective in forming public opinion today is because of "globalization", which allows media outlets to obtain very reliable information from all across the globe at an unprecedented speed.
