I've delayed answering partly because of RL and partly in the hope that inspiration would strike and I could start to understand you position a bit better. Needless to say I don't think it has. I suspect this may be one of those things where we are never going to 'get' the other's view. needless to say that does not mean we should stop trying, but I have to confess I am no longer optimistic.

For now, I'll concentrate on the smaller stuff and see if an overall pattern becomes clearer to me.

I shall start by splitting a hair because it is there to be split.
as a result of my rejection of positivism as self-contradicting, non-empirical principles must exist
Ouch. If your sole rejection of positivism is that it is self-contradicting then logically you can only conclude that non-empirical principles could exist, not that they must. If you are going to say 'must' then you need some element of proof.

I would argue--even if I'm not sure how to demonstrate--that your position is necessarily inconsistent, in that insofar as we're having this conversation in language, it's always-already implicitly and intrinsically ideological; it's built into the landscape. From your perspective, what does it really mean to "understand" my position--we're just altering each other's brain chemistries by modifying the patterns of the photons hitting each other's retinae (retinas?), right? (Which, obviously, is going on, but that's not the point.)
The only possible answer to that is 'Yes. So?' Because as far as I'm concerned we are indeed talking in language and it is therefore shot through with our cultural and biological histories (which is what I take to mean by 'built into the landscape') so each one of us is bringing vast accumulations of 'stuff' to the conversation in addition to our own personal experiences and opinions, just as we do to any conversation. And all of it as far as I'm concerned has an origin, there are no Ouroboors floating in space without any history, just chains of cause and effect. So if I want to understand the origins of ideas I look to social history, and behind that to ecological imperatives and brain chemistry, with which, of one could trace it back far enough, one could find the origins of conscious thought. None of which would matter in terms of difference between my views and whatever it is that you in fact believe except that we are talking about ethical issues, we are not just saying 'this is' but 'this is and it is right or wrong'. Now under my system, the closest I can come to 'right' is 'currently acceptable by the society I live in' or 'something that I perceive will be to my advantage or the advantage of those I care about' (the two are of course frequently the same). And I have to acknowledge that my value of 'right' may therefore change over the course of time, as indeed history shows me has happened for as far back as we can observe. I'm not quite sure what you standard for 'right' is but it seems to be more along the lines of 'something I feel to be right after due consideration', and I am still very unsure where you believe these ideas to have their origins. If I can understand where you think your ideas come from, and if I can relate it to where I understand ideas to come from, then I will feel in a position to both 'understand' why you believe the things you do and to make up my own mind in a more informed manner as to whether or not I agree with you.