That may not be unique to college campuses.
It may also be the case that many college students grew up in low crime environments, since college attendance is skewed toward those from higher income backgrounds, so that they do not have any particular concern with avoiding and preventing crime (i.e. their guard was never up). When I went to college, many students were extremely careless about leaving doors and property unattended and unlocked, to the point that thefts were extremely common. Obviously, lack of crime awareness can also extend to violent crimes like assault, robbery, and rape.