The simplest response is that for a vast majority of true beleivers, their religion of choice (or more accurately the religion of their family/geography) provides something satisfying to them. That something may be a sense of community when attending church, it may be a lessening of the inherent fear of their own impending demise, it may be hope for a better future, etc. etc. etc.
The vast majority of the people on Earth have some sort of beleif in a higher power. I watched "Contact" last night, and they listed the figure at around 80%. I don't know how accurate that is, but it seems reasonable to me. An idea of a higher power looking out for you is comforting. Especially so when you are having hard times, or when you are being abused in some way. And face it, the vast majority of the people on the planet go through significant hard times and abuse.
I really think the appeal of Christianity/Islam, etc. . . lies largely with the promise of a reward in the afterlife for beleivers. It is comforting when you are going through something painful, discouraging, or tedious, that better times are ahead. What better way to get through a day, or a life on Earth which is often filled with pain and torment, than to beleive that all this suffering is but an eyeblink compared to the vast expanse of the eternity you will spend in paradise.
For most beleivers, this is, at worst a benign delusion, and at best, the ticket to an eternity of bliss. There are, of course, bad people involved in religion, just as there are bad people involved in any organization. I too have a problem with religious fanatacism, and don't relish the idea of an overly religious person having any say over my life. So to some extent I can agree with your sentimentality, and I do think religion in general has caused more divisiveness and strife, and torture and war over the centuries than probably any other human concept, but . . . .
Most of the people on this forum who identify themselves as religious, are not fanatics. There are a few running around who probably wouldn't mind hearing about an abortion clinic exploding, or an infidel losing his hands, or an athiest receiving a good beating, but I would venture that those types are very very few and far between on this board. Not too many people with that level of mentality are going to be able to get a computer turned on, hooked up to the internet and navigated to this site for you to debate with.
Most religious people, are quite simply, just most people.
Even most people who identify themselves as religious, when they sit and think about it, will agree with you, that religous matter defy logic. On occasion you will have someone posit Paschal's Wager in an attempt to apply logic to the debate, but that begs many other questions which generally cause the debate to devolve.
So, that was a long way around the barn to say, that religion still exists today, in spite of our realization through the natural sciences that a lot of what Western Religions have told us (Flood, Geocentrism, Jonah/Whale, Age of Earth) etc, etc. etc. are incorrect, because . . . religion fills a need that the believer has. That need may vary from believer to believer, but it is there to provide something that each individual beleiver needs, or wants, in their life.
B.