If there is evidence to the contrary, wouldn’t you want to explore it if you really want the truth? Wouldn't you be excited? Why would you hold on to this theory so fiercely? What have you got to lose if it is proven to be in error? If you stopped believing in evolution, what would have to be your alternative belief?
Consider for a moment. Put yourself in their shoes.
You may just have to admit to God’s existence and his hand in creation.
And if you admit to that, you may just feel compelled to respond to God’s existence and consider what he has to do with your life. You may find yourself in a position where you have to openly land squarely on God’s side, or openly reject him.
Are you up to the challenge? What do you have to lose?