Because religious leaders have proven corrupt and not credible. Because they can see religious people around them being bigoted and hypocritical. Because God doesn't seem to help people, even innocent infants, who are abused, starved, sick, or accident victims. Because religion is often a con by control-obsessed people who want power and influence over our bodies and minds. There is a better way.
Crime is highest among the religious.
Christ denounced public prayer. The bible is pro-choice.