This is how mankind is wired. Once we accept something as a foundational belief, it takes a lot to change it. This enables us to operate in daily life, as we don't have to reassess our entire worldview every time we're exposed to new information. If new information seems inconsistent with our foundational beliefs, we just do some mental rearranging to make it fit, until that's no longer possible. In the meantime, it's much easier to keep rearranging the furniture than it is to rip up the house by its foundation.