There comes a point for all of us where we simply have to make a decision: either we choose the flat, gray neutrality of belieflessness, or we choose to see the world in the dynamic contours of faith.
When you believe in nothing—or, rather, when your belief is that there is no right or wrong, no good or bad—then everything becomes the same. Giving your grandma a hug versus, say, a punch in the face is totally neutral as far as morality, according to this view. The truly principled neutralitist will refuse to judge any one circumstance as being better than any other. But most adherents are quite human (as we all are) and succumb to considerations of self-interest. This totally relative comparison then pervades and colors everything, but, in essence, there is still only one reality: me. It’s not that pursuit of self-interest is inherently evil. But, of course, neither is it inherently good.
When the morally-positive paradigm is assumed, on the other hand, another metric for choosing one thing over another comes into play. Aside from “What’s in it for me?” there comes to be “Is it right?” These two imperatives can be sharply divergent. It seems like, even sans penalties imposed by society, something like embezzlement would be highly approved of by the self-interest imperative, but disapproved of by the morality imperative. These moments of divergence often become a defining experience for the believer, for choosing something other than what raging self-interest dictates both proves and reinforces belief.
There is no such divergence for the self-interested neutralitist, and thus there is no self to overcome, no hill to climb, no peak to summit, no view to behold. Just flat, boring, static neutrality. Even meeting all of the demands of self-interest brings no satisfaction for, in the neutral paradigm, after death there will be no “self” to remember how much of its interest was achieved, so why achieve it at all?
Which leads to another issue: no morally neutral paradigm asserts anything about the post-death self other than “It ceases to exist.” Why is this? I believe it results from a combination of two things: first, if an individual first comes to believe that death is the end of the self, a moral neutrality frequently follows due to the elimination of incentives; second, though I’m purely speculating here, if an individual first comes to a stance of moral neutrality, belief in post-death persistence of self might suddenly seem irrelevant: if there’s no right or wrong here, then it’s probably because there isn’t any there either.
Likewise any moral positivism that denies the persistence of self past death saps itself of much of the incentive for the believer to follow the moral imperative.