Thanks, Angela, this is really fascinating. The one thing I disagree with is your comment that newly-diagnosed young adults with T1 are not the "norm." The vast majority of new-onset Type 1 is in adults, and new onset Type 1 is seen in all ages (even Joslin commented on this in 1934). That T1 is a childhood disease is just a myth.
On a different note, my godmother was diagnosed with Type 1 as a child in 1928. My mother said that she was always very controlled about her eating and weighed every morsel that went into her mouth. There's the Joslin influence. She lived a relatively long life for someone diagnosed in 1928, so there is anecdotal evidence that the low carb approach is preferable to the "eat anything you want" approach.
Finally, blaming people for non-compliance and high A1cs is SO harmful in so many ways.