I'm not trying to be insulting, but why do most evangelical Christians check their intellect at the door?

This is not true for all, but for many I have met. I don't think logic and reason were tools given to us by God just to ignore. But if you challenge many Christians on their world view, many resort to simply quoting Bible verses, or spitting our b platitudes, or just run and hide altogether. It can be frustrating, especially if these people are your friends or acquaintances. Because they feel OK "sharing" with you, which is always an obvious veiled attempt at conversion, but if you "share" with them any opposing viewpoints, you just get treated poorly.