I think one of the biggest reasons there are a lot of atheists and agnostics (especially among teenagers) is because they do not understand religion and religious teachings/where they originate from. People who say "Christians base everything off the Bible" or "Religious people don't believe in science and hate gays" and such are utterly lost and very ignorant. I used to be atheist, but once I took the time to actually learn about religion and religious teachings, I came to understand it. So many people are quick to dismiss anyone who identifies as religious and hold themselves in a higher view because they believe they have it all figured out. Sadly, its often the exact opposite.
Excuses are nails that build the house of failure
~Laura was here