One of my Facebook “friends” is someone I need to keep track of for a personal reason. No one who knows me would ever think this is someone whose opinions I agree with in any way. He posts the most vile, racist, homophobic stuff you could imagine. The only way I could get access to his posts (which, as I said I need to see for personal reasons) was to friend him.
I don’ think this was what happened in the Harvard student’s case but it does run counter to the idea that someone’s friends always give an accurate idea of the person’s views.