Like you, I'm not going to go on and on about this too but I'm having trouble understanding your explanation. (I'm not trying to necessarily agree with you; just understand with you. I can agree to disagree.)
I've seen mold and dryrot in all shapes and sizes. But in the attic, it's a result of the moisture not getting out of the attic; NOT a problem getting out of the living space. So, if there's mold and such in the attic, it's the attic that needs proper venting; NOT a vapor barrier installed in the living space. And contrary to what you say about too much moisture, if there's mold and mildew, it seems obvious to me that either there's too much moisture or the 'space' isn't properly vented.
Your ending note, ... I have to disagree with from the perspective that, well, it's OK for moisture to condense BUT it has to evaporate and GO somewhere. Yes, it will rot, so why would you put one in the attic? The moisture will condense on the under side / warm side of the barrier and rot the ceiling, right? That's why I don't see them installed in attics. And I respect your position not to put one in but I professionally disagree why you WOULD with your reasoning. I'll stop here but I'd really like to hear more.