During the Cold War the Soviets and NATO constantly sniffed each other and by the late 70's they acquired a good sense of protocol about how to behave around each other.
However the PLA never acquired that protocol and so it is back to square one with them. Once we reach a level where both believe it's Ok to sniff on each other as part of the peace, then P-8 flyby will of no consequence.
For the PLA, no one is trying to humiliate them anymore. They got Hong Kong and Macau back peacefully under the agreed treaties. Taiwan is a different situation that again, will just need to be worked out through rational dialog. Not by lobbing missile tests across the strait 2 days before elections.
Yes, everyone including the Japanese agree that what happened in Nanking and Manchuria was wrong.
But exacting penance through military action will not recover a loss of face almost 80 years ago.
One must convince the PLA that face can best be restored through their economic capacities and their ability to dialog on even the most difficult of subjects.
However it is well known that the PLA embraced a new level of military capacity after NATO bombed their embassy in Belgrade during the meltdown of Yugoslavia. Never mind that Chinese intelligence was allowing Serbian intelligence to use their antennas to communicate with the field. The PLA did take that as a direct loss of face and they have vowed not to allow it again.
Their feelings about it are the same as our embassy taking in Tehran when the Shah fell. When you think of it in those terms, then you see why they get worked up.
The dialog with them must continue.