I think a lot of it may have to do with people who haven’t developed much of an independent self-identity, they compensate by attaching to one or more already established belief system and when new knowledge challenges that belief system they feel personally attacked.
I used to be fairly active in the Christian church when I was was younger, but now I’m to the point where I have no problem with the theory put forward by some(like Tom Harpur in the book Pagan Christ) that Jesus Christ wasn’t even a literal figure, he may have been created from previous belief systems. But it took a gradual process of several years for me to work through to that point.
Knowledge comes with a certain responsibility, for instance if you accept the well founded theory that by adding more and more greenhouse gases to the atmosphere it will result in climate change that can have some serious consequences then that knowledge may come with the need to largely reorganize how we live on a social scale. There are ethical and moral implications with being open to new ideas that some people don’t seem very well equipped to handle.