That's stacking the deck against atheists by considering militant atheists. What does that mean to you? Do you prefer militant Christians over militant atheists? Militant Muslims over militant atheists?

All I meant was an atheist who is as invested in his belief as the committed Christian is in his religion. My committed Christian friends go to church regularly, read the Bible frequently and attend study groups on it, have a strong preference to marry a fellow Christian, and so on. They identify primarily as Christians. I suppose the atheist equivalent would be someone who is a member of the BHA or atheism+ or similar, reads Richard Dawkins, whatever, and strongly identifies as an atheist. These people are not rare, and are in fact overrepresented on lesswrong.

There are also people who don't believe in God in the same way that he doesn't believe in unicorns, and gives the two ideas the same amount of thought. Or indeed, the Christian who never thinks about God. I don't perceive much difference between these two.

Or, a fake invisible friend who makes you hate a lot of people. Who makes you miserable about your sin. Who makes you afraid of eternal torment.

Yes, anything is theoretically possible. And it's a big old world, so no doubt there are even one or two people like that. But in point of fact, the way it works out is that Christianity tends to make people more generous, caring and trustworthy than atheism does. So it goes.

EDIT: To be fair, if you are arguing that the reason committed Christians are nicer than committed atheists is that professed Christianity attracts nicer people whereas professed atheism attracts jerks, then this is also consistent with observation, but I prefer the causal story.