R: Your Friends Should Share Your Values

Christ's Parable of the Tares in Matthew 13 seems to promote tolerance among mankind. When weeds were planted among a man's wheat crop, he does not allow his servants to pluck them up lest the wheat is killed in the process. Are "bad apples" really so harmless as this parable suggests? In our increasingly global society, we are likely to live and raise our families in communities whose members do not share similar goals and standards of conduct. Should we be discriminate, befriending only those who validate and encourage our moral character? Or should we widen our social circle to include just anyone?