It's because we have a mind set against him...
Yes they're serious.
My reply to them was simply this..
I couldn't get past the first paragraph without shaking my head. Sorry but lack of evidence is EXACTLY why i and many atheists i talk to on a daily basis refute the idea that there is a god. How can we have a mindset against something we refute as being nonexistent? That's like an adult being mad at Santa because you didn't get the present you wanted.