Signs of Broken Fellowship

Perhaps people do not disconnect themselves physically from the others, but their relationships remains superficial. There are many possible reasons for that.
Some people may seem to be faithful to their church family, and on the surface everything looks fine. However, if our ears are very sensitive, we may hear them confide that they don't feel loved; they feel alone or isolated. They feel that no one listens to them. They may complain that church doesn't do anything for them, or is boring. They feel starved. They may or may not eventually go somewhere else to find "food" and acceptance. In this family the vital ingredients of fellowship are missing, and that means that the church is vulnerable to predators.

Hypocrisy is a symptom of broken fellowship with God and with each other. Hypocrites believe that their church loyalties are satisfactory to God. They become proud and lose sensitivity to each other. They disconnect themselves from the "sinners". Gossip and criticism are some of the many ways that hypocrites break fellowship. They can't see their sin, and don't realize how much it weakens the fellowship. It is like stabbing your own toe.

Many churches these days want to be tolerant and accepting of everyone, and so they end up inviting the lions right into the fellowship. But lions are not the same as needy, straying sheep. They believe that they are enlightened by God, and use their influence to pull others towards themselves. They justify their sin and convince others that it is okay. After a while the sin feels right. The people become proud because they are so "enlightened" and "open minded". But they don't realize that by being cozy with lions, they have made their fellowship vulnerable and weak. 
Scripture has a word for them:
And you are proud! Shouldn't you rather have been filled with grief and have put out of your fellowship the man who did this? 1 Corinthians. 5:2

Leaders who are disconnected from God either desert the flock by neglecting it, or they quench the Spirit by lording over the members, stifling their spiritual development. They cannot discern the work of predators within their own hearts or within the rest of the Body.