I don't talk about God because I know He exists; I talk about God because I know you exist. Movies like "God's Not Dead" grossly misrepresent atheists. Allow me to make a few corrections. You're free to express your religious beliefs; I wouldn't want to take that from you.
Your beliefs are not free from my criticism. Don't think for a second that just because I freely give my criticisms, that I'm a secret believer. That isn't even logical. Have some empathy. Understand that I'm critical of your beliefs for many reasons: they affect my life, they're untrue, and I simply find it interesting. Fair enough?