I'm sure most people have known theists who are smug and condescending toward those who don't believe the exact same form of "truth" that they themselves believe. They're easy enough to see. I've known quite a few in my time.
I've also known a few atheists who are smug and condescending toward those who believe in any form of theism. These aren't hard to find, either, provided you look in the right places.
Some might say that there's no difference between the two groups. And essentially, there isn't. There is, however, a difference of appearances.
What I mean by that is that there are plenty of these sanctimonious theists who pretend not to be. These are the ones (and there are plenty) who claim to "hate the sin, but love the sinner." They claim to love their fellow humans, no matter what their beliefs, and only want to see them "saved." But behind these claims lie opposite sentiments. Behind the façade is the real "truth" to them, which is an attitude of superiority and a silent condemnation of anyone who thinks differently than they do.
Basically, they're hypocrites, pure and simple.
As for the "superior" atheists, I have yet to meet one who has such an attitude and doesn't admit to it readily. I admit that I went through a phase like that, not long after college. I got over it, but the point I'm trying to make is that I never pretended to be otherwise.
To me, this behavior in theists is revealing of the duplicitous nature of religion in general. Religion is full of deception, full of untruths. It's only natural that many of its practitioners should be the same way.
