Hackers target universities because universities are known for having very lax security.
Hackers share information with each other about their exploits, and easy targets. Computing and networking professionals are aware of the very real dangers posed by hackers. You may feel that no one would have any reason to break into your computer. Thus, network security is the responsibility of everyone connected to the network. Creating, using, and updating passwords on a regular basis is the first line of defense against hackers.