In fact, Mao destroyed everything that he felt was detrimental to the state. Much of China's history, the richness of this millenniums old society was lost. Depriving people of their history is depriving someone of their human rights. A person has a certain amount of aesthetic needs. To many, history is what is aesthetically appealing.
History is used so one can learn about the past and what one can do in the future.
In a democracy, history would be nothing to worry about. But to an oligarchic government history and thinking is scarier than foreign invasion. If what we call the deprivation of human rights are welcomed by the majority of the people we have no right to say it is wrong. An American has different ideals and principles than a Canadian, or a Chinese person. When we were shocked and appalled by the caning punishment used by the Singaporeans we sneered and ridiculed and that is our right.