Denying facts because they conflict with a belief is a survival tactic for the human race. We all do it. But now it seems a lot easier for everyone to have their own "facts." On the Internet you can find "facts" to justify any opinion. Of course, observable, provable, documented facts are out there, but we must be smart enough and honest enough to pick them out of the sea of fake facts.
Here is a good example, in a recent letter defending the Obama administration, I claimed that, "Illegal immigration is currently net zero." That means that there is just as many illegal aliens leaving the country as are entering. If true it would call into question the fear that the country is being overrun by illegals. This number can be quantified and documented and thus can be a real fact. So how do you determine that it is a real fact and not something made up because someone wants it to be true?