The open threads are the proper format for arguing
against others' beliefs.
If a Catholic thread is posted saying "Mary is the co-Redeemer" (as there have been many already) how is a Protestant supposed to reply with anything other than by the negative "No, Mary is NOT a 'co-redeemer' because according to the Bible, there is ONE only propitiation for our sins, ONE mediator between God and men, ONE Redeemer, Jesus Christ?"
You would reply in the "for" - using the last part of your example:
According to the Bible, which I believe is the final authority, there is ONE propitiation for our sins, ONE mediator between God and men, ONE Redeemer, Jesus Christ.
You would reply in the "for" - using the last part of your example: According to the Bible, which I believe is the final authority, there is ONE propitiation for our sins, ONE mediator between God and men, ONE Redeemer, Jesus Christ. So on an ecumenic thread, we could not preface that comment with "No, Mary is not a co-redeemer because...?"
Because sometimes that phrase is simply used to redefine the discussion when replying to a post from a few days earlier.