I find it interesting how most people can stubbornly take perspectives in life for granted as 'good' or 'bad' without thinking why those values are deemed 'good' or 'bad'.
People are like sheep in that way, I think. When another person whose morality is supposedly 'superior' to you says so, people in general just aren't capable of questioning the foundations of such statements; they'd much prefer just to follow.
So what happens when that moral structure, where that other person whose 'moral superiority' you follow bases his supposed superiority, is questioned? What if it is ultimately shattered? What happens next? Is your 'humanity' destroyed as a consequence?
Maybe that's why people are so afraid to not believe. Not believing gives you two things, a paradox: on the one hand, a vast, expanse of sea where you can chart your own destiny; on the other, a lack, an absence, a void. The former, freedom; the latter, emptiness. The first will test your capacity to face fear; the second will test your capacity to overcome nothingness.
And both gifts scare people. People are afraid of too much freedom; most prefer to be slaves. And the illusion of "realness" for some is much better than real absence. A promise of a shadow of a thing, though an empty hope, is better than the very real knowledge of its nonexistence.