The organization disfellowships and shuns members who disagree with doctrines. Some do not leave quietly and therefore become enemies.
Jehovah's Witnesses are warned against associating with and even greeting all Jehovah's Witnesses who are disfellowshipped, - whether they say anything negative about the organization or not. 
Jesus said, 'Love your enemies and pray for those who persecute you, that you may be sons of your Father in heaven. He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous. If you love those who love you, what reward will you get? Are not even the tax collectors doing that?' Matthew 5:44-46.