The most nefarious thing that college does is take young people at a vulnerable age and at their first real separation from their families and familiar structures and values and pump them full of liberal nonsense about how they should live their lives or how society should be run or changed. Most people outgrow this to some extent after exposure to the real world, but I think the effects remain in people's minds like a low grade infection, particularly around many social issues such as single parenthood, the gay lifestyle, etc. And don't forget the education in vice. College is the devil's playground, by and large.