Well, bear in mind that there are respectful ways to express one's opinion as well as disrespectful. If I say, "I think you're ideas are a bunch of crap, but it's simply a fact, so don't get offended," it's a little different than if I said, "Well, I feel that because there is no evidence for what you believe, it cannot possibly be true." You tend to speak in terms of the former, when the latter would certainly come off a little less condescending. You do realize that there are brilliant people who understand the Bible and its contradictions and that there are challenges to one's faith in a secular and scientific world, brilliant people who are indeed quite scientific themselves, who still believe in God, right?