Something I saw raised a question in my mind: An MD-80's T-tail had
one half pitched up and the other half pitched about neutral. My
question is why any T-tail aircraft would allopw differential motion
of the two halfs of the horizontal stab? It seems to me that the
rolling couple such a position would impose in flight would act as a
tremendous shearing force on the fin.

I'm no kind of structural or aero engineer but does any military
aircraft with a T tail support differential movement of the two halves
of the horizontal stabilizer?