You basically answered your own question with your last sentence.
The world is stuffed to the frigging gills with people who put up firewalls against the obvious to maintain their beliefs (and not just in religion). And not just dummies, either. Now that's an empirical observation.
There are at least two, maybe three threads in the past couple of weeks where people have simply slammed the shutters down rather than acknowledge facts they didn't want to deal with, and had no counter to. And this board is a relatively small sampling of humanity.