People get off on knowing things others don't. To "be in on" the secret. It's an ego thing. "I'm open minded enough to accept these things" or "I'm not sheep", or "I'm enlightened"
These people have taken the concept of an "open mind" and completely blown it out of proportion. It used to about being more accepting of different people and ideas, such gay rights, rejecting anti-drug propaganda, or not being a bigot towards other cultures/religion. Now it means "reject all science and makeup some shit that sounds good." I like to say that I keep my mind open, but these numbskulls have taken over the term and stupefied it.