When a Christian foundation interviewed college nonbelievers about how and why they left religion, surprising themes emerged.
…They had attended church
Most of our participants had not chosen their worldview from ideologically neutral positions at all, but in reaction to Christianity. Not Islam. Not Buddhism. Christianity.
The mission and message of their churches was vague
These students heard plenty of messages encouraging “social justice,” community involvement, and “being good,” but they seldom saw the relationship between that message, Jesus Christ, and the Bible. Listen to Stephanie, a student at Northwestern: “The connection between Jesus and a person’s life was not clear.” This is an incisive critique. She seems to have intuitively understood that the church does not exist simply to address social ills, but to proclaim the teachings of its founder, Jesus Christ, and their relevance to the world. Since Stephanie did not see that connection, she saw little incentive to stay. We would hear this again.
They felt their churches offered superficial answers to life’s difficult questions
…Michael, a political science major at Dartmouth, told us that he is drawn to Christians like that, adding: “I really can’t consider a Christian a good, moral person if he isn’t trying to convert me.” As surprising as it may seem, this sentiment is not as unusual as you might think. It finds resonance in the well-publicized comments of Penn Jillette, the atheist illusionist and comedian: “I don’t respect people who don’t proselytize. I don’t respect that at all. If you believe that there’s a heaven and hell and people could be going to hell or not getting eternal life or whatever, and you think that it’s not really worth telling them this because it would make it socially awkward…. How much do you have to hate somebody to believe that everlasting life is possible and not tell them that?” Comments like these should cause every Christian to examine his conscience to see if he truly believes that Jesus is, as he claimed, “the way, the truth, and the life.”
https://www.theatlantic.com/national/archive/2013/06/listening-to-young-atheists-lessons-for-a-stronger-christianity/276584/