Being a theist, I will disagree with the delusional part..
However, those Christians who say that are portraying Christianity and God in a very arrogant light. It's like saying God cares not for those who do not believe. If any Christian says that, I'd say, "But if I'm praying, isn't the fact that I'm praying a testimony to my belief in God after all?"
Really, they give this argument but they mean:
"If you're not a Christian like ME and MY CHURCH and MY PASTOR define 'Christian' to be, then God will not answer a single one of your prayers. Be like us, or you'll be sorry!"
BALONEY. God listens and answers. Not only that, who the hell is anyone to speak for God? Can a Christian read a person's heart, deep down inside where no one can see? Are Christians given special eyes to see and special ears to hear?
Only God can judge the heart. Christians haven't the capacity.