The police are responsible for enforcing the law. As peace officers, they make arrests of those who make a decision not to follow rules most people agree to. It doesn't matter who someone is, the police are still going to take that person into custody. As long as evidence exists to make their case, they have a legitimate reason to do so.
Many an actor has being a member of law enforcement as part of his or her resume.
Television networks have long made a police department a part of their lineup. Shows such as NYPD BLUE, CSI, and Law and Order will always be watched even if the episode shown is a repeat. Viewers enjoy watching cops catch the bad guys, which helps to increase ratings.
In fact, the popularity of police shows gives various law enforcement groups the opportunity to gain new investigators as a result. In these cases, people see themselves as able to perform the same types of jobs.