Man-crush Steven Novella writes awesomely on germ theory denial:
Denialism is always fascinating – the bold-faced denial of facts that are fully in evidence and easily verifiable. It is a testament to the profound psychological effect that ideology can have on the human brain, and the mechanisms by which it is maintained. And before we wax too self-righteous as skeptics in this regard, we must always remember that we are all susceptible to these psychological mechanisms. We are all human. That is precisely why we need the rigorous, transparent, and self-critical process of science to sort through complex questions such as disease and immunity.
I’m stealing his conclusion here, but the whole thing is very much worth reading.