Ever hear a child put his hands over his ears, or sometimes closing her eyes too, and chanting loudly, "I can't hear you - lalalalala"?
Aside from the old adage that "there are none so blind as those who will not see", there are different names for this concept, such as "selective ignorance" and "self-imposed ignorance". I often use another term, because I think "willful ignorance" fits better due to the fact that it takes a conscious decision to decide to stay ignorant about an issue on purpose - especially when there is so much information available. We are surrounded by it, and so as far as I'm concerned, to remain ignorant about some things must take a supreme effort of will.
Ignorance is not knowing something, and ignorance in itself is not such a problem - people closing their minds and being willfully ignorant, is. Some people are unwilling to accept facts or information that will either contradict their beliefs, or relieve their ignorance - precisely because the facts or truth will disprove their beliefs. That is what happens when people become set in their ways, old and inflexible. It is the same with belief systems. The same could be said for languages - when they stop growing and changing to keep up with the people who use them, they become obsolete and die. Basically, what I am talking about here is resistance to change.
Likewise, it's amazing how fragile religion can be, how like a house of cards? When its continued existence rests on the continued denial of actualities and facts, because the pillars of that religion have come to rest on assumptions, mistakes and outright lies instead of the foundations upon which it was supposedly founded?
Take an example. Some people who belong to a particular religion, say Christianity for instance, hate gay or transgender people. They say that gay and trans people are "evil" because they are gay or trans, and they use their religion as an excuse for their hate, and drum up other people who feel the way they do into a frenzy of anti-gay and anti-trans sentiment - leading to exclusion, discrimination and persecution.
The gay and trans people say "stoppie bus", protest - and say they didn't choose to be gay or trans, and in any case most feel they were born that way. Just ask Lady Gaga, she'll tell you. The haters refuse to accept this, maintaining that being gay or trans is a "sinful lifestyle choice" and see this as relevant and fitting because all "sin" is a choice. The ringleaders attempt to mask their hate by making idiotic statements like "hate the sin and not the sinner", clearly not understanding that our expressions of love or self-identification are precisely part of who we are as people, and obviously not realizing the brute stupidity and implications of such a statement.