I think that our 6000 year old earth is to blame for much of this mess. The world was once Officially Flat, the church eventually had to cede that point as science proved otherwise. Science has unequivocally demonstrated Evolution to be truth and that the Universe is 13.7 billion years old, or so.
The religious minded will have to cede this point just like they had to abandon the Flat Earth, and Earth is the Center of the Universe theories.
Anyone who will take up their Bible and read it, starting at the beginning will find not a book of love and wisdom from a Good God, but a horrid, bloody history of a murderous bronze age tribe of people. It's a book filled with hundreds of cases of genocide and ethnic cleansing. Incest, murder, child-molestation.
God and Jesus both had nothing bad to say about Slavery, something you and I KNOW to be wrong.
The early church was a widely varied thing. Congregations and denominations ranged from the purely aesthetic to the orgiastic, both in the name of Christ.
The Holy Roman Catholic Church rose to power because Rome's military might had waned, and they needed a new way to control the people.
They stole Christianity, warped it's books to meet their ends, and exterminated those who wouldn't go along with them.
So effective were their techniques that few had the bravery to stand against them for over 1500 years. Martin Luther led the first great Evolution of Christianity.
I believe another one is happening now. People are beginning to read their bibles and see them for what they are. Repositories of ancient truths, wisdoms and atrocities, that have been edited for the purpose of controlling the masses.
With a 6000 year old Earth and Biblical understanding of human nature... the Devil makes you lust and do various selfish acts.
With a 13.7 billion year old Universe and a 4.3 billion year old Earth, we are descended of a long chain of animals. Our brain is the result of eons of evolution and posesses structures very similar to the brains of crocodiles, with structures on top of it not terribly dissimilar to those of rodents, birds and "lower" mammals. We have a slice on top that makes us aware, conscious and gives us free will, if we can realize that we only "use 10%" of it.
The trick is, that other 90% isn't just sitting there, it's the Devil. In it lies those base, reptilian desires of lust, hunger, rage and fear. In the mammal structures we have compassion, love, devotion and altruism. And in that 10%, we have reason, logic and morality.
I like to think of it as the Father, the Son, and the Holy Spirit.