You'll see it over and over again. People believe what they want to believe and what they want to believe is often what is in their best interest to believe. Don't get me wrong, people do not set out to close their minds to opposing points of view, but it usually takes an overabundance of evidence by a trusted party to convince anyone to change their minds, no matter how intelligent they are. As a corollary; the longer someone holds a particular view the more difficult it is for that person to change that view.
Of course I could be wrong, but you'll have to prove it to me.