The other half of my theory goes as follows;
Theists base their beliefs on one thing, just as atheists do. This is (obviously) what sets them apart so strongly. Theists, at the core of their being, are based on faith. Atheists are based, at the core of their being, on logic. This is what sets them apart like oil and water. Atheists can never understand faith, and while some theists can understand logic, their faith is stronger. Atheism-theism is a battle of faith and logic, and you really can't say that one is stronger than the other. Well you can, and invariably someone will try, but until you can actually use your logic to disarm others of their faith, you can't honestly believe that one is stronger than the other. And if you honestly believe you can rid someone of their faith with logic, you're as misguided as any Catholic.
Honestly though, why the hell would you even try? Faith works for so many people, it causes strife, but it brings millions and billions of people together under one banner that honestly might not even look at each other otherwise, and that's something that I can get behind. Atheists might be joined under a unifying cause, but honestly, what have atheists ever done as a group? How many soup kitchens feed people who are under their luck because of atheists? How many houses are built in New Orleans every day because of people who don't believe in a god? How many people stop drinking or shooting up or wasting their lives because of the lack of faith?
At the other end of the spectrum, how many scientific breakthroughs have been garnered by people foaming at the mouth about a god? I'm sure that one day the cure for cancer will be realized or the solution for world hunger will be realized, and it might be an atheist who stands at the helm of that discovery, but I can promise you this much. She/He will not attribute that breakthrough to her/his lack of faith. It will be a discovery made by human effort, not the belief or disbelief in a god.
No, faith does save people, even if it's illogical. Ultimately that's what it comes down to. An atheist could never understand why someone would give up all their worldly possessions and wealth to sit down and take care of people less fortunate than them, someone willing to sacrifice their own well-being just to aid others.
Similarly, someone filled with faith could never understand why someone would claim that everything their life is based on is fake, simply because there is no rationale to it. If there's no proof, there is no god. But that's the thing about faith that atheists don't understand! God doesn't matter without faith! If someone believed in god simply because there was proof, he would be meaningless. Everyone would go about paying tribute to someone that they know exists and it would be fake. Someone else here already mentioned that if they knew god existed, they'd believe in him just to go to heaven.
But theists don't believe to go to heaven. Theists believe because faith gives them strength, and the strength to help others. Which is why I respect them a hell of a lot more than I respect atheists. It's easy to believe that there is no god because there is no proof. It's hella hard to believe in god when there isn't any.
Especially on the internet with all the atheists cramming their logic down your throats.
As for what Max already said, yes there are fanatics for every religion, or lack thereof. And it's not a good idea to throw the baby out with the bathwater. However it only takes one bad apple to ruin the bunch (that's the end of the metaphors for today), and that's why I left the Catholic church. It only takes a few judgmental assholes to make you not care about god, and similarly, it only takes a few anons filled with their newfound logic to make the rest of you look like fools.
At least in my eyes, but like you said Max, everyone is arrogant of their own beliefs.
Edit: My bad, the last paragraph or so probably could've been a pm.