When you go to criticize another for what you consider a foolish belief, think of the following: If you were born and raised with the belief you consider foolish, would you also believe it? I think you have to assume there's at least a chance you would. If you admit that there's a chance you could believe something foolish, and not realize it, then you have to admit you could be living in that ignorance right now, and you would not know it.
They say a fish is the last one to learn about water. The same can be said about people and their perceptions. The only way to see the water is to step out of it. Until we step out of the water of our perceptions, we're just fish carried by the currents.