I think each person has to make up their own mind on religion. I think part of the problem is that many can't talk about their faith rationally, but resort to something like, "This is what my Book says, so it's true, because God inspired that Book, because it says so in the Book."
I totally understand why some are belligerent towards religion--religion has caused pain as well as good, and many religious people I know think their sh** doesn't stink. As someone with religious beliefs, I also understand the positive ways that faith can impact one's life. Christians kill, Muslims kill, atheists kill, there's enough blame to go around. We all share one planet, whatever we believe.
With regards to C.S. Lewis, I don't see what the big stink about him is. I read his Mere Christianity last year, and I think he was trying to rationalize things that can't be rationalized... he didn't convince me of much of anything. His analogies of "begetting" for explaining the trinity made no sense to me whatsoever.
"And though I may not know the answers, I can finally say I am free. And if the questions led me here, then I am who I was born to be." --Susan Boyle
"If all fools could fly, the sun would be eclipsed forever." --Dutch proverb