"If you don't believe in this thing for which there is no evidence at all, then you are completely out of reality!" - you.
You know, I wanted to be religious, I tried for years, but never for one second did I believe any of it, though I liked going to church.
If God existed and wanted us to believe, then He could just give clear evidence of His existence, but there is none. Any argument you use about your Christ can be used for Allah or Satan.
Why does God play these hide-and-seek games with us? Why doesn't he just spell out the rules? Is God really obsessed with stopping buttfucking and not particularly interested in stopping war, as modern Christians have told me many times?
Simple answer is that there's no one there. There's absolutely no evidence at all. You twist the complete and total lack of evidence for your God (or their Allah or their Zeus or their Ahura-Mazda) into evidence of existence!
I might add that atheists believe in sin much more than Christians do - you have been misinformed.
Sin is not a big deal to a Christian because no matter what sin you commit, God will forgive you if you ask - the Remission of Sins.
Atheists don't get Remission - we have to live with our sins for our whole lives.
You Christians can sin and sin and sin and sin all you like, and as long as you get good with God, you're completely forgiven.
This is no doubt why so many leaders who are publicly Christian in America are also such horrible, dishonest and deceitful people - because God forgives them every time.
That's also why there are so few atheists in jail. Unlike Christians, we must live with the consequences of our actions.