Not losing anything is a poor reason to be a Christian, or to belong to any other group.
There are three main reasons why atheists assault the beliefs of theists. The first is simply that it's sad to see other people be wrong about something so important. The second is that if the beliefs are false, which is likely, then theists are spending a huge amount of time, energy, money and emotion on something which will not reward them in the way they hope. They're losing a portion of their lives.
The third is that theism often breeds animosity towards atheists, and most other theists.
It is possible to be rational about some things and irrational about others, just as it's possible to be right about some things and wrong about others. We all do it; we think of a shirt as lucky, we play the lottery despite the expected outcome, we approach the beatiful woman who we know will knock us back. No human being is rational all of the time.
Religion often invites and allows irrationality by discouraging people from seeking evidence or questioning doctrine. Scientists and other such intellectually driven people might even relish the chance to relax their faculties now and again, and be swept up in the community of a shared belief.
It is also possible to be both rational and religious because being rational doesn't mean being right. Incorrect premises in people's reasoning can lead them, perfectly rationally, to an incorrect conclusion. The premises on which religions base their truth claims are incredibly hard to pin down.
Your examples of rational theists are not good examples. Franklin was a deist for much of his life, and even as an elderly Christian held "some Doubts as to [Jesus's] divinity". Einstein did not believe in a personal god, or anything which could contravene the laws of the universe. He effectively thought God WAS the laws of the universe, and this is to what he referred when he used the name. He was something like a pantheist, and basically said so: "I believe in Spinoza's God, who reveals himself in the harmony of all being." I encourage you to read up on Franklin, Einstein and Spinoza. They're fascinating people.
Short answer is that they don't. Atheists generally leave open the possibility that there's some kind of god. It's just that they judge the probability of that to be so small that it can be dismissed. It's like living in Los Angeles knowing it could be destroyed by an earthquake any day; you can't say it'll never happen, but you take the overpass to work anyway.
Atheism is a-theism, the lack of a belief in gods. It's not a positive belief in the absence of gods. It's not a belief or a faith at all, simply a conclusion. The premises leading to that conclusion are roughly as follows:
- A god is an incredible, unprecendented, almost unimaingable being.
- To accept the existence of an incredible, unprecendented, almost unimaginable being would require strong, definite evidence of some type.
- No strong, definite evidence for any such incredible, unprecendented, almost unimaginable being is available.
There are all sorts of stoushes going on over what constitutes evidence, whether a priori arguments can be accepted in lieu of evidence and even whether we can decide this rationally at all without a god to provide logic, but it still boils down to these premises.
No and no. It's 2008 now, for a start. Sorry for the lateness of this answer.
Religions with an eschatology component (end-of-the-world hypothesis) work hard to make doomsday sound imminent. This gets harder as time goes on; the Jehovah's Witnesses had five "last" days go by before they stopped making specific forecasts.
The reason is that people are more likely to act if they think time is running out. The fear of missing out can be intense. It's just like an ad for furniture that says, "These deals will not last, so hurry!"
Every religion wants now to be the end times, because it's the equivalent of a closing down sale. Whatever people have done in their lives where they fear judgement, they can get square with their gods at the eleventh hour and be safe. It's great for recruitment and fundraising.
The next scare will likely be in 2012, because the ancient Mayans' calendar simply runs out that year. They didn't happen to say why, but surely if the world was going to end they'd have written it down. That would be a red letter day indeed.
It does sound silly when you put it like that, but it's not the best criticism when you look closely. In the Gospels which actually mention the virgin birth, Mary was already pregnant when she married Joseph. God didn't have to screw her anyway; it was a sort of divine artificial insemination. If He had screwed her, it wouldn't be a virgin birth.
It's fun to find inconsistencies in the Bible, but it's been around for a very long time and apologists have had ample opportunities to restore its internal consistency through extremely convoluted logic. Otherwise nobody would dare declare it to be inerrant. It will take more than an accusation of hypocrisy on God's part to actually shake someone's faith.
There are a great many issues with the truth claims of Islam. I suggest starting by searching Wikipedia for "Historicity of Muhammad" and working from there. Do not take Wikipedia at face value, of course.
Unfortunately fundamentalist Muslims, like any other religious fundamentalists, will not generally accept criticism of their religion. Muslims who lose the faith, apostates, are marked for death. Non-Muslims are infidel and not to be trusted. You can see how it's difficult to attain a platform from which you'd actually be listened to.
Don't take it for granted that if Muslims were presented with evidence that their beliefs are false, they would abandon them. It would be far easier to believe that the evidence itself is false or, even more cunningly, a test of faith.
Nobody wants to be a traitor, but that's currently the only official way to leave Islam. Fundamentalist Islam especially has insulated itself against Muslim and non-Muslim reason alike. It'll be tough to inject any.
It makes no difference after death, it's true. But it makes a huge difference to your life.
Compare the life of a liberal Christian to the life of a fundamentalist Muslim, or that of a Hasidic Jew to that of a Shintoist, or that of a Scientologist to that of a Mormon. Now compare them all to the life of an ordinary guy who sleeps in on Sundays, donates blood regularly and doesn't think any supernatural being owns a piece of his time.
That's what difference it makes.