Re-reading the whole thread, I don't think we disagree on much.
No, I don't think we do.
I think the fundamental difference is that I attach imprtance to whether an utterance is good, or natural, or appropriate language. You attach more importance to grammaticality and logic.
Just to be clear, when you say "more importance", more than you do, yes, I think that's fair to say. It's not that I attach more importance to grammaticality and logic than I do to good, natural, appropriate language. I hope that's not what you meant!
I really think that a major problem related to all this is what stems from a member's original question. As we all know all too well, learners often ask the wrong question. They'll ask things like "Is this sentence grammatically correct?" or much worse— "Is this sentence correct?" when really they just need us to tell them whether what they've written expresses well (whether that means clearly, grammatically, sensibly, elegantly, concisely, etc.) what they mean to say and, of course, whether it's appropriate to whatever situation it's going to be used in. That's why we demand to have context, right? So we can see the intended meaning and use of the utterance. The temptation to answer these questions with a mere "Yes, it's grammatical" can be quite strong on busy days. Sometimes, such an answer is the right one, but often, it's unhelpful because any technically 'correct' answer is completely besides the point.
If it sounds like I'm blaming the learners, it's because I am!
No, seriously, as I think teechar was pointing out the other day, a big part of our job is to help learners ask the right questions in the first place. I can't overemphasise how important I think this part of our jobs is. That's what I tried to get at, unsuccessfully it seems, way back in post #5.