The "Fact" of evolution is undeniable, JWs wisely avoid debating the subject with those that have gotten a higher education as they are ill equipped by the Watchtower corporation's selective information indoctrination/studies on the subject.
The cognitive dissonance caused by a discussion with some one worldly that has a higher education on the facts of evolution with some one indoctrinated to believe it is false would be almost unbearable and be cut short by the JW because of how uncomfortable he was feeling.
It is even painful for me to watch a JW trying to argue against evolution because I can still feel a twinge CD, even though I'm no longer a believer in the biblical deity.