So, why the willful ignorance? Fear of the unknown and a reliance on what has worked in the past.
I think willful ignorance is necessary among many fundamentalists because their beliefs are contradicted by the evidence from the real world.
They either accept that evidence, to the detriment of their beliefs, or agree among themselves, and with themselves, to ignore that evidence. To do otherwise would require that they question, or even discard, some of their beliefs.
We've seen here that some of our fundamentalist posters will cling to the flimsiest of support for their beliefs rather accept than the overwhelming contradiction of that belief.
Ignorance of science is an integral part of that willful ignorance. If one were to study science, one might begin to question one's beliefs. Better to remain ignorant of science and firm in one's beliefs? That often seems to be the case.
But the problem is that the willful ignorance becomes an impervious cloak; no fact or evidence from the real world may be allowed to penetrate that cloak if it may be detrimental to one's beliefs.
Willful ignorance is the worse kind.
Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.