Well I wouldn't judge her excuses since she's still not really understand about this forum rules.
Which forum rule are you referring to?
But AFAIK when account already changed hands, the account will get negative feedback just like this thread [1]
Not necessarily. While it is a standard practice to that (at least in the majority of cases) there are no rules that account that changed hands has to get negative feedback and each case should be seen separately.
I personally wouldn't leave negative feedback in this case simply because of the honest approach and I think that neutral would suffice to warn everyone that account changed hands.