The great leap forward was failed economic policy and overzealous application of ideology. The intentions were good but the outcome was disasterous.
Up to 30 million Chinese died when counties played a game of one upmanship to beat neighbouring counties in food production. The higher the declaration, the larger the amount of grain that was given to the state.
Mao was starting to lose it by this point and various high ranking party members were aghast at the ill effects of their policies in the countryside.
In China, legitimacy of the communist party is of paramount importance. Fail too much and the mandate of heaven is lost. Society collapses and a dark age comes about thus failures by the CPC is covered up. Its a ham fisted approach and most Chinese already know of the past failures of the communist party.