In wandering off on my tangent about Christian morality, I could have framed my objections much more simply.
Why be moral? Why should anyone perform moral acts? If there is an answer to this question then morality is an end to that means. If there is a promise of a reward in Heaven, then morality is a means to that reward. If the justification for morality is possession of a good conscience, or pleasurable feelings, or some other pleasurable experience, then again morality is a means to that end. And if morality is the avoidance of some threatened unhappiness, then has as its originating impulse fear.
Why is this important? This means that the end to which moral actions are to be performed is more important than the moral actions themselves. Further, there are situations, however improbable, in which the end to which moral actions are performed will be in contradiction to morality.
The perversity of morality, especially Christian morality, is that it can only be justified by appeals to immorality.
Alternatively, if one should be moral for the sake of being moral, with no promises of a reward, as well as no threats of punishment, either in this world or in the one to come, then why be moral? An answer cannot be given. Morality cannot be justified, nor defended, nor even praised for any reason that would in itself be consistent with morality. Consequently, the question why be moral? not only goes unanswered it, the question is unanswerable.
The Evangelicals avoid all of those conundrums simply by appealing to divine fiat: follow God's Will or go to Hell. However comforting Evangelicals may find their surrender to God, their justification of their surrender is the same as that of any other coward's acquiescence to an inescapable bully: might makes right. By appealing to God's power over His mercy, rationality, or other qualities, they create a whole host of other problems. Some of these I've touched upon in other posts. Some I hope to treat more explicitly.