A very interesting question.
I would not be close friends with people I did not care for. But I can listen and have a conversation with them nonetheless. But I would deliberately avoid contact with people who I believe had truly evil dispositions. I would not be rude, but I know I could not feel comfortable socializing with them.
A puzzle: if you would shun a child molester, but never shun your family... would you shun your child if s/he were a child molester??
My answer: no, not necessarily.
bebu