From a late night discussion
Of course, first of all that's a ridiculous statement. There are plenty of religions world-wide that aren't Christian and yet which hold equally implausible beliefs - if you're going to mock those that profess the belief that a simultaneously triune yet whole entity that created the universe sent a part of itself to Earth 2000 years ago to save us all from our sins, you have to mock the idea that the Shiva Lingam is 5000 miles long.
Secondly, while I have no trouble acceding that atheists, as far as I can determine with my human senses and the information currently available to me, are certainly right in that the universe as it exists does not require the hand of an inscrutable deity or deities to function, I find the contempt towards those that profess faith to be baffling. Of course, as an agnostic, I believe that the ultimate truth of our existence is unknowable as long as we are human. But even if for the sake of the argument we divorce ourselves from that point, I find intellectual contempt for people based solely on their choice of religion (divorced from what they do with it) to be puzzling at best and repulsive at worst.
Faith is belief in the absence of evidence: it's an ability humans have had for as long as they've been able to describe themselves as human. Like any human ability, when it is used positively (to prevent despair in the bare face of the unknowable fate that awaits us in death, to allow us to achieve cultural bonds with each other and share through ritual our common experiences as humans) it is a very fine thing. When used negatively (to scorn those who do not share our beliefs, to try and impose them on others because that's what God/Kali/the horned one would want, as a justification for intolerance and bigotry) it is a very bad thing. There is no question that throughout history religion has been used to justify genocide and wholesale torture.
There is also no question that throughout history economic systems, scientific inquiry and the possession of land have also been used to justify genocide and wholesale torture, yet no one seriously advocates that those things be done away with, much less treats all of these involved with those processes as imbeciles. (I shouldn't say no one, as I'm sure you could probably find someone who does on the internet with minimal effort.)
If you have made the intellectual choice after working through the various factors of human existence that there is no deity or deities, congratulations. You are to be applauded for having made the effort. You may well be right. That mere fact no more justifies your intolerance of others than it does their intolerance of you, and the fact that you have decided that religion is silly does not make those that have not made the same decision as you stupid, or lacking in the facts you have in your possession. They may in fact be stupid. They may in fact lack information you have. But they may not, and until you know one way or another, treating all people who profess to a faith as if they were cretins does you no credit.
This of course leaves out the fact that as an agnostic I find any such declaration to be monstrously arrogant. I do, but I don't go around calling atheists and people of faith monsters of arrogance based solely on that decision. You're free to swing you arms around until the point where they would collide with my nose.

