I'm not sure what happened in the meantime.
May I suggest, totally off the wall, that she recognized the economic advantages of normalization with China and did not want these advantages to occur under a Republican president? This cynical guess could be bolstered if we could determine when she changed her tune.
I'll bet all those campaign contributions that China sent to the DNC had something to do with it too. And to think, all that the Chinese wanted in return was a few nuclear secrets.