1) Because of people like Perry and Vinny. Much as Jeff Foxworthy of 'You might be a redneck if" fame has said in his comedy routine: "I hate the fact that everybody thinks southerners are ALL stupid. There ARE smart southerners, we just can't keep the dumbest among us off the tv". There are rational, thinking religious people who I, as an atheist, can have an intellectually stimulating discussion with, where we can agree to disagree. Then there are the other people.
2) Because of personal life experience. I could make a list, but egad, where to start? One example of an experience I had was with a very religious drill instructor in Marine Corps boot camp. In the orientation phase at the beginning of boot camp, he proudly stated that he had an unbroken record of 100% platoon participation in chapel services on Sunday, going back x number of years that he had been an instructor. Not being stupid enough to buck him in front of the whole platoon, I approached him privately to tell him that I would not attend services. I was threatened with court martial (a bluff, he knew he couldn't, but I didn't...yet), given extra duty, and generally became the low man on the totem pole in the platoon due to all this. He made it his mission in life to harass me and assign me extra duties and 'shit details' whenever something came up. On Sundays, he would force me to march with the platoon all the way to the chapel (a valid order I could not disobey), then play headgames with me on the front steps in an attempt to force me to attend, and finally, each week, when I refused, would send me running back on the double to stand guard duty in the empty barracks.
3) Because of misconceptions. Many theists need an education on what an atheist is. I can't count the number of times I've had talks where I revealed to someone that I was atheist, only to have them respond by saying something along the lines of "Oh, but you seemed so nice...how can you worship satan?" By definition, atheism is without theism...without religion...satan is a product of god, without one, the other is just as meaningless. Too many religious people have been indoctrinated to a polarized belief system, "if you are not of the body, you are of the world" or however you wish to put it. I am outside the mold. I refuse and refute your definitions. God and satan are two sides of the same coin, atheists have NO coin.
4) Because of placating and patronizing. By which I mean, these sort of statements: "You're an atheist? It's ok, Jesus loves you anyway" or (see my military experience above) "There's no atheists in foxholes", or "you just haven't seen the light yet, one day you will" or "ooooh...you used to be a JW, no WONDER- you just had a bad experience with religion"...as if, had you only had the RIGHT experience (which of course, usually means attending the church of the one making the statement), all would be smiles and rainbows, you poor silly misquided child, you.
5) Opinion: On this board at least, which has a rather unique set of group dynamics, because of a desire to share...enlightenment...freedom? Not sure how to put it... I will attempt to explain. Most of us here had a bad religious experience, and fled the JWs (or in my case, the Worldwide Church of God/Armstrong). I think many here desire a shared experience of newfound freedom, a sense of relief that it wasn't all true. Having escaped the frying pan, and become atheists in the process, I think many of us look around and feel a need to express that in some way, and share the escape experience with others, only to be dismayed when they see that to the atheist way of thinking, some have escaped the frying pan only to fall into the fire. I think a lot of atheists think that with just one little push, they can make the believer convert to the truth. "They've come halfway, maybe they can make the next intuitive leap." In a sense, many of us are just as guilty of proselytizing as evangelicals.
