You're cherry-picking one statistic to judge Mao's leadership.
On its own merits, life expectancy is going to be difficult to evaluate China on during this period. Mao's government followed from both a disastrous Japanese invasion as well as a disastrous civil war. Wikipedia says Mao's policies were responsible for 40 to 80 million people dying. Do the life expectancy statistics account for that? How does that compare to the performance of Western governments during the same time period?
On its own merits, life expectancy is going to be difficult to evaluate China on during this period. Mao's government followed from both a disastrous Japanese invasion as well as a disastrous civil war. Wikipedia says Mao's policies were responsible for 40 to 80 million people dying. Do the life expectancy statistics account for that? How does that compare to the performance of Western governments during the same time period?