Good question. But I believe the main reason is that people don’t read their bible for themself and just let someone with a false gospel teach them a lie.
Churchianity is attractive to those who do not know their Bibles. Churchianity assures people that they are right with God because they listen to sermons or keep certain rules or attend meetings in a church building. Churchianity produces nominal Christians who fall under the same condemnation as the religious leaders of Jesus’ (and Isaiah’s) day: “‘These people honor me with their lips, but their hearts are far from me. They worship me in vain; their teachings are merely human rules.’ You have let go of the commands of God and are holding on to human traditions. . . . You have a fine way of setting aside the commands of God in order to observe your own traditions!” (Mark 7:6–9; cf. Isaiah 29:13).
It could be argued that churchianity is the fastest-growing religion in America, due to the proliferation of its messengers via TV and the internet. Although churchianity is more widespread now than ever before, it is nothing new. Second Timothy 4:3 warns, “The time will come when people will not put up with sound doctrine. Instead, to suit their own desires, they will gather around them a great number of teachers to say what their itching ears want to hear.” Lack of religion has never been the problem; lack of truth has. As sinful human beings, we are always seeking that which validates our opinions and agendas. When we find that validation stamped with a Bible verse, we feel justified in rejecting the difficult path of discipleship in favor of this glitzy promise.
Because it gives the appearance of being true faith, churchianity challenges true discipleship as an attractive counterfeit. Churchianity wants to look good sitting in the pews, but it won’t demand real sacrifice. Churchianity carefully avoids some obvious sins while tolerating other, more socially acceptable sins. Churchianity encourages religiously minded people to make half-hearted, costless decisions that offer false assurance but never result in life transformation. In the current Western religious climate, churchianity may be the greatest threat facing true Christianity.