Jessica Sideways addresses the question of why she criticizes theists. My church runs around 50/50 theist, though I've never heard an atheist express him or herself with Jessica's bluntness there. Pretty much all of it is stuff that has been addressed a million times, either you take Jessica's position or you don't.
A few examples in direct response to Jessica's examples: Yes, lots of blood has been spilled, theoretically in the name of God. Either you accept that in defending their God the people who spilled the blood got to put themselves in charge and that even more blood has been spilled over people wanting to be in charge with various other justifications, therefore were it not for religion those inclined to spill blood would just pick another reason, or you don't. I do.
Before the invention of the microscope, anyone who believed in bacteria had to, at best, say that their theory that bacteria existed was one of many theories that were possibly true. They could not show anyone bacteria or in any way prove that is wasn't imaginary. The people who didn't believe in bacteria were perfectly rational not to do so as the claim that bacteria existed surely sounded like a fairy tale.
But the people who believed in bacteria were still correct, as the invention of the microscope would eventually prove. So there is at least some precedent, in science no less, for people to believe in things they can't see and can't prove exist at this moment to turn out to be correct.
There are lots of people who justify science and religion co-existing various ways. To give my Christian parents' views as an example, which I like to do since they are smart folks, God designed a world that could be left on its own to grow and change. One of God's greatest gifts is freedom and the freedom to chose a mate that creates evolution is part of what plan God has, though it isn't our place to know God's plans, the degree to which things are planned and/or the level of detail. Stories like Adam and Eve and the Great Flood are meant to be taken as metaphor and if you think about them, provide valuable lessons. Biblical admonitions against the eating of shellfish that sound crazy now made a hell of a lot of sense in a world that wouldn't develop refrigeration for another couple of thousand years. Even if you don't believe that the ten commandments are God's rules, they make a lot of sense and we would live in a much more pleasant world if everybody took them as good advice and followed them.* Etc, etc, and soforth.
To further expand on the point, in an argument at Steve Caldwell's blog once, I made an analogy that I've always sort of liked, comparing belief in God to my appreciation of modern art. I assume for the sake of argument that one "chooses" to believe in God or not, something that I don't necessarily believe**. Anyway, I'm going to edit it what I wrote a smidge and re-post it here.
Dale McGovern wrote: Many, many theists express their supernatural belief as a necessary alternative to a world they otherwise see as cold, wonderless, and devoid of meaning.
CC responded: Just because someone says "A world without God would be cold, wonderless and devoid of meaning" does not mean they are choosing to believe in an imaginary God to please themselves.
I could say "a world without modernn art would be cold, wonderless and devoid of meaning" and that doesn't make Picasso a creature of my imagination.
You don't have to believe in modern art for modern art to exist, after all, and if modern art doesn't enrich your life, that doesn't mean that modern art isn't valuable to some people.
Steve Caldwell wrote: Given the amazingness of the natural world, do we need to "gild the lily" by adding a supernatural layer to this world we live in?
CC responded: You can say "Given the amazingness of the natural world, why do we need to 'gild the Lily' by having an style of art that focuses on finding new truths by looking for new ways of seeing and considering new materials and the nature of art itself?" all you want but:
1. Modern art still exists.
2. It's still a valuable thing that enriches the lives of those who appreciate it.
3. It gives a new perspective and new truths to those who believe in it and understand it.
At the same time, lots of people decide that modern art is a bunch of hooey and don't bother and/or only look at more representational older paintings.
Since much of the discussion has centered around a "What you see is what you get world," I will put my response in that framework.
If you don't go see Modern Art, you will never get it. You will get other things that you do see, but you won't get what you decide has no value and not to look for or at. If you superficially examine modern art and dismiss it without really understanding or appreciating what you're looking at, it's really not very surprising that you don't get much out of the exercise.
And that's up to you and fine, until you start saying "I don't see any value in modern art, so modern art must be valueless for everybody else, too."
* As one who is still considering divorce law as a potential profession, it saddens me to admit that they have a point there.
**Sitting right where you are, just for a moment, choose to believe that the moon is made of green cheese.
Go ahead. Do it. I will wait.
Can't do it, can you? Even if you really, really, try?
IMHO, all belief works about the same way. You believe or you don't and your desires to believe or not don't have much to do with it.
I have met one guy who, when given this exercise, claimed that he was able to turn on his belief in lunar cheese and turn it back off again like a light switch. That dude sorta scared me.