Well, curiosity is definitely more of a survival trait than a danger. Our brains are wired to assign meaning to the world, and how well we do that has certainly been one of the driving forces in the ascension of our species. At some point in the long distant past, man started trying to plant crops. When the crops inevitably died, our ancestors didn't give up, they were able to figure out the "why," the reason it had happened, and correct it. If the reason was, "not enough water" they corrected it by watering the crops.

Our brains are designed to ask why, to develop the best hypothesis we can, and to run with it. The question is, what happens when the world is too complex for us to figure out. I think that history shows that what we do is basically make something up. We develop religion or superstition to answer the why questions, and just do the best we can. What you jokingly call stupidity, I call the result of curiosity combined with a lack of ability to understand "why." Fortunately, the world isn't too complex for us often enough to kill us.

But basically, I think there are two types of woowoos. The first type is the person who knows he's wrong, but makes something up just to get attention. It's really not hard to do. The other type of woowoo, I think, is a person with a substantial need to understand the world, but without the resources to do it. In any case where our brains are wired to do something, we wont feel comfortable unless we can do it. That's what instinct is all about. I think that the people who we call woowoos have a substantial, overbearing need to understand why things happen. But for whatever reason (maybe they just didn't pay attention in high school) they don't have the ability to understand or accept the mainstream explanations, but they absolutely have to fill that need.

Look at the bright side, that drive they have is what keeps pushing our species forward. It isn't a bad thing at all.