Wow.There's a lot here, but I'll try.
First, a conclusion can be reasonably drawn even if it is not supported by explicit articulation in one or two verses. It is not a Scriptural standard but part of an extra Scriptural tradition to insist on 'Chapter and verse' to support a doctrine.
Second, it seems to me that IF one considers what Paul says about the Spirit in the believer and the believer in Christ, and the number of times that he says something like, "now I," and then it's almost as if he catches himself, as he says something like,"yet not I but Christ lives in me,"or not I but Christ working in me," then one can devlope the thought that by dying in Christ and being raised in Him, the Christian now operates in Christ, (or Christ's life operates in Him) and he (or Christ in him) carries out Christ's work.
To say it another way, it is a fruit of the astonishing redemption wrought by Christ, a redemption far greater than we could have imagined, that he now shares his life, himself, and his work with the saints.
To use a piece of dispensationalist jargon, I think one should "rightly divide" lie from falsehood.
My primary complaint against calling Mary a Co-Redeemer is that she had no part in the actual redemptive work on the Cross. I understand and fully support the adoration and honor that the Catholic and Orthodox Churches have paid to Mary, as this is completely Scriptural and is not something which I would speak against. That said, however, I cannot in good conscious declare Mary a Co-Redemptrix due to the fact that it was Christ, not Mary, which provided the blood sacrifice for our redemption back to the Father.
I completely understand that Mary willingly acted as a vessel to carry the Christ child in her womb, and for that we should do as the Scriptures state and honor her above all other women, but the act of redemption cannot be performed by any other than Christ Himself. Mary, for all of her honorable actions, could not provide the perfect, sinless sacrifice which the Father required, only Christ could fill that requirement and because of that only Christ is worthy of being called the Redeemer of Mankind.
As for the "Mary Ishtar Worship" or whatever it is that Quix calls it, while I don't think that most Catholics intend that their adoration of Mary be viewed as worship, the similarities are there to the point that some have began to fear that the same demon who seduced the Babylonians into worshiping her has infiltrated this portion of the RCC. This, coupled with Mary's status within the RCC as co-redeemer has many of us outside of the RCC worried quite a bit.
I hope that this begins to explain some of our hostility towards what we perceive as Mary worship.