A logical and rational person simply says that, in the absence of evidence, the existence or non-existence of the entity is irrelevant...
Whilst I have agreed with you so far in this thread this I can not agree with. A logical, rational and scientific minded person would say there is no evidence for the theory yet there can be no absolute proof against therefore I believe in all likelihood there is no god, due to the lack of evidence, yet I can not categorically say for sure and would change my position immediately upon the presentation of affirmative evidence. I believe this is, for example, Dawkin's stance.
You are seeming to indicate that if a position can not be adequately explained we are to adopt a position of ambivalence with a wholescale lack of curiosity which seems to be me to go against the whole drive behind scientific discovery. There is little evidence for and against a great number of theories and we would not have made the leaps in medicine, physics etc if we had just said oh well can't suss this one let's knock it on the head as a don't bother. Maybe this is not what you are saying but that's the way it comes across to me (bear in mind its just past midnight though and the brain cells have gone to bed).