No system is perfect. Nothing in Western democracy can prevent a new Hitler.
And Mao is only considered a tyrant by Western media, but a hero to most Chinese, and Vietnamese like myself as well (he helped Vietnam a lot, unlike Deng Xiaoping who attacked Vietnam). Most countries in the world, sooner or later, will need a Mao to correct the bad aspects of societies, resulted from years of laid-back governance.
Very likely within 20 - 30 years, you will see that the US (and most Western countries) need leaders like him, rather than your current talking-only leaders, especially when many Western economies are going down the road.