[fretelöo]

Speaking of "me" in the first answer, was meant as a short rhetorical twitch. Substitute "Current Catholic Theology, in Spirit with the Vaticanum II and as Currently Lectured by any Non-Reactionist European Catholic and - for the Most Part - Protestant Theological Faculty".

This might be a slight overstatement, but if it is, it really is only a slight one. And, frankly, what some radical christian sect somewhere in Idaho preaches, is of relatively little concern to me and to my on belief (oops, did it again).

As to your general point: The thing is, that the simplistic part is precisely your notion of what a definitive answer is. A definitive answer is not necessarily something that can be proven ("proven" in any strong sense of the word). And that must be so, for if otherwise, either all believers or all non-believers were simply stupid, not up to the intellectual task of understanding the other side's arguments (skimming over this thread seems to yield a few supporters of this view). And I (and again, take that as "Current blabla") don't think it's that easy.
So, you have to think of a notion of "definitive answer" that doesn'T rely on a strong notion of "proof".

And there are such notions. They rely on conditions such as consistency, rationality, "translatability" (in the sense of being translatable to other cultures normative codes) etc.

That isn't arbitrary. Someone claiming that there's a loving God that just happens to hate all homosexuals and rather wants them dead then befouling his beautiful earth, might find a few citations in Leviticus, but his "theory", if you want it call it such, is by no means consistent with his suppositions about what God is/means/wants.

If you take some scripture citations about how all non-believers are not worthy of living, that collides very much with every notion of the "God of mercy and love" that those same people say the NT is all about, that might be rationalizable by some quirky way of thinking (say, something to the effect that death is better than a life in sin or so), but it's definitely close to inconsistent with a somewhat broader picture, incorporating Creation of Mankind with free will etc. etc.
(I just give those very crude examples, because if we go into detail, we'll, for one, leave the actual point of discussion (i.e. notions of definitive answer), and for two, get into really deep waters of philosophy, dogmatics and fundamental theology. And I'd rather avoid those for the time being)

The thing is, that anyone comming from a scientific background always feels "tricked" if you come him with the idea that something can be non-arbitrary, yet at the same time there's no hard proof. I'm having these discussions for years now with my father.
Either you come to terms with that way of thinking (and the whole of human sciences basically relies on this kind of arguing) and can grant it validity, or you can't. It's that simple, really.