Religion can be a place where evil conceals itself.  It can be a platform from which self-centered people look down on others as a way to mask their own sickness.  We will run away from bold evil.  So evil comes to us pretending to be good and right.  Religion is often a vehicle to promote an agenda.  Christianity with its teaching of humility and self-denial is adverse to this.  Yet there will always be tares growing with the wheat until the day of judgment.

“Beware of the false prophets, who come to you in sheep’s clothing, but inwardly are ravenous wolves.  You will know them by their fruits. Grapes are not gathered from thorn bushes nor figs from thistles, are they?  So every good tree bears good fruit, but the bad tree bears bad fruit.  A good tree cannot produce bad fruit, nor can a bad tree produce good fruit.” Matthew 7:15-18 (NASB)

From “The Disciples And The Teacher”, by H. Lamar Smith