Even during korean war, china did not outright kill American Prisoners. ISIS is a lot more barbaric and determined to kill westerners than china ever will or has. China wants to be seen as gentle and humane, not barbaric like ISIS. ISIS is far more ruthless towards the west than china has been. Mao is not the type to put all the eggs in one basket. He leaves diplomacy open, while ISIS and osama clearly is more militarily determined to leave no prisoners and no diplomacy open for reconciliation with the west. Simply put china is more interested in internal threats, while ISIS is determined to destroy all westerners. China is complicated and has a large population, it is not interested in expansion the way ISIS is. ISIS wants to create a caliphate in the middle east, while mao and the communist party already has power in china. Communist party is interested in preserving its power and even cooperate with the west in order to prosper. ISIS is determined to destroy the west if given the choice. There is a huge difference between china and ISIS.