All about looking better in the eyes of their fairytale deity ....

.. and what better way than converting as many as possible?

http://www.truth-out.org/how-fundamentalist-mind-compels-conservative-christians-force-their-beliefs-you/1332095126

Beliefs have consequences, and one consequence of evangelical belief is that decent people end up doing ugly things in order to recruit converts and save souls. It is because they care about being good that they do harm. In the much quoted words of Steven Weinberg, “With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion.” The mechanism by which this happens is that religion creates a narrative in which the evil serves a higher good.

Check out the bit about the 4 moral emotions one particular religion in the US uses (Guilt, Shame, Embarrassment, and Pride )...

http://www.psychologytoday.com/blog/the-literary-mind/200911/the-four-moral-emotions

But recent research on emotion has shifted the traditional focus away from the "basic" emotions to another set of emotions which are thought to be more distinctly human. Focus has turned to the "self-conscious" emotions, which are sometimes also referred to as "moral," "social," or "higher-order" emotions. These are the emotions that an organism can only feel if it has a highly developed sense of self-reflection. Usually, the "self-conscious" emotions are listed as these four: guilt, shame, embarrassment, and pride.

I'd say it's just another way to delude one self into thinking and acting as if one is better than anyone and everyone else. And ... in the process, suspend any practice of rational thinking or acting.