Ian:
You seem to miss my point entirely . From your example it seems that you're working from your own subjective stereotype of what a given belief system should or should not hold as true (albeit it is one that many people hold in common)
Further, you actually make my point, in that you acknowledge that there are some Buddhists who believe in reincarnation (I hadn't missed that this isn't your personal belief, as I saw you write something about it last week, hence my use of that particular example ). Within the same group reference you accept that there are differences of opinion regarding beliefs and standards of behaviour.
You cite the "human" explanation as an excuse, but to some it's a reason, not an excuse. Just because you got it in first and dismissed it doesn't weaken it any. Regardless of an exoteric identification with a given group, individuals will not neccesarily hold to all the mores or beliefs of that group, and indeed why should they be bound to? Because others feel they should?
The whole basis of your initial argument is founded on groups of people having to maintain a particular standard enforced upon them either from within the group or from without, whether from their contemporaries or a Deity.
Specifically in the case of Christianity, ironically the higher standards are usually imposed from without, because usually those within are acutely aware of their own foibles. I include in that judgemental group those who follow the Christian religion but would confess that they aren't Christians in the esoteric sense.
Within the same irony is that those who are not Christians in the esoteric (broadly "gnostic") sense usually remain fearful of death and attempt to work for their "salvation. Are they hypocritical when they fail to meet their own exacting standards? Maybe, but they're still only human.
Back to your original premise, you are of course entirely correct. IMHO many people adhere to some religious belief and occasional practices precisely due to the fear of death, as you suggest. It's just not all of them, and I strongly suspect that the group on this board is not representative of this faction.
It's funny how the term "religion" seems to bring out the highest ideals in people, whether they can meet them or not, huh?