You could argue that manhunts are not interesting, but I believe that they are. In the case of serial killer's they show the ways that the person tries to escape capture, irregardless of whether or not they are intelligent or not. They are also invaluable in keeping the population informed on what is going on.
In the era of reality TV shows, the most fascinating news stories to watch involve manhunts. Many are captivated by watching law enforcement pursue the most wanted suspects and criminals. Furthermore, news companies oblige their audiences with round-the-clock coverage of such events. In fact, news coverage of some high-profile manhunts have even preempted regular programming.
Many people follow the news and social media when a manhunt is underway. However, it is important to remember that this is not entertainment. A manhunt occurs when someone has committed a crime. It is important to remember the real people involved and to not take a salacious pleasure in the police action.
If you are interested in the drama and risk involved in a manhunt, then yes, they are interesting. Following clues and investigating a person's steps could be very interesting to one person, but other people may disagree due to the level of risk involved. It's interesting to follow, but also important to remember safety measures.