To be precise, 31% of Christians take the Bible literally, down from 38% in the 1970s when there was a big Evangelical push that everyone take the Bible literally. Fact: Over 60% of Christians never took the Bible literally. What I find irrational is atheists arguing with a minority belief over stories instead of philosophies.
Wouldn't it be more rational for atheists to argue over the philosophies--i.e., the Ten Commandments, the Beatitudes, Wisdom, etc.? Also, most Biblical references to Satan (HaSatan) reference temptation or a Tempter. In other words, in most cases, temptation is personified. Both in the desert and with Peter, Jesus insisted that these temptations get behind him.
I have read enough current studies on possession that there do seem to be rare cases of demon possession. The interesting part of these various studies make the observation that in the rare, true cases the person does, in some way, invite Satan (or demon) to enter within.
What is irrational for atheists disdaining Bible stories is that they never see past the setting to the purpose--which is the lessons or moral--of that story. They argue with the minority, truly a case of the blind leading the blind.