First of all, refer to this article:

http://monthlyreview.org/commentary/did-mao-really-kill-millions-in-the-great-leap-forward/

TL;DR: The article talks about how the anti-Mao perspective was encouraged via funding through Farfield Foundation—a CIA front—which wasn't disclosed until years later (1967). The original numbers (16.5M) for Mao's famine during the Great Leap Forward (1958-61) were released under Deng's administration (1979)—which needed to discredit Mao's policies in order to make radical changes—and are based on statistics inconsistent with other famines, internally irreconcilable when considering social practices, and accompanied by unknown gathering methodology. Also, the massive death toll hypothesis hadn't ever been taken seriously by anyone until Deng. Yes, there was a famine. This had been known and wasn't actually unique to Mao's time, but it seems to have been blown completely out of proportion to provide political justification.

The vast bulk of deaths (30 million by most western scholars) attributed to Mao are starvation deaths during the Great Leap Forward. I'll shorten this down into bullet points for the sake of brevity. Some of these examples are practical pieces intended to alleviate guilt, some are defense against the inflation and skewing by Western media attempting to portray Mao in a specific light.

-Statistical death figures during Mao's rule attribute all deaths to Communist Party policies.

-Crop failure has occurred throughout Chinese history, in fact Chinese history is punctuated by periods of acute crop failure, saying that the CCP is strictly to blame is unfair.

-Crop failure was exacerbated by the peasants themselves devoting time towards industrialization rather than agriculture.

-People dwell a lot on the era under the CCP, but not a whole lot about the reason the CCP was so successful in China. The truth of the matter is that before the CCP the country was controlled in large part by corrupt warlords, and a highly corrupt nationalist government. Peasants had next to no rights. Conditions were absolutely deplorable. China had been wrung dry by the Japanese, and the Communists had been betrayed and massacred by the Nationalist (supposedly allied) forces earlier in the war. Mao spent 17 years in the countryside building support amongst the poorest and most abused of the Chinese people.

-Decline of birth rate is a result of crop failure, and is a historical certainty anywhere in the globe. Less food = Less people being born. People love to attribute "Population should have increased by X so they must have been killed!" arguments to Mao.

-Advancement in the party was closely tied to performance, this created an incentive for low and mid level party members to over-report grain harvests. The shortfall would then have to be made up by the peasants. In prior years lets say Town A yielded 200 tons of rice. A corrupt official reports 200 tons produced, the government asks for 100 of it, 100 gets eaten by the town. In reality only 150 tons were produced, the official is pressured to meet previous quotas and says 200 was produced. Government asks for 100 again, but this time only 50 tons are left for the people. In this way Mao was mislead about the true situation in parts of the countryside.

-Mao seems to get all the blame for the failures of the Great Leap Forward, despite the fact that it was the work and policy of the entire standing committee.

-The Cultural Revolution was a revolutionary movement against reactionary forces inside of China itself. As was evident from the USSR's slide back into capitalism, the strongest pull of capitalism came from within. Mao feared China following Khrushchev into revisionism and towards capitalism, everything hinged on instilling revolutionary ideals in the youth. He called upon the students, workers, and peasants to rise up, and they did in large numbers. I wont shirk from what happened, this is the nature of communist class struggle. The capitalist supporters eventually won. When Mao died in 1976 he predicted that capitalism could soon return to China, and indeed the current "Communist Party" is headed by billionaires. China is a vastly more unfair place now.

At this point it should bear mentioning some of the successes of the Chinese Revolution and Mao thought.

-Average life expectancy had risen 25 years

-An industrial base had been developed in a primarily rural country (though it certainly never hit Maos hopes due to failures in the idea of "backyard steel furnaces")

-Large advancements in healthcare and education

-Land reform that took lands from vast landowners who kept the peasants enslaved in shackles of debt.

-Restored the mainland to central control (wrested from warlords)

-Stamped out the rampant inflation they inherited

-Fought off imperialist forces in Korea (under the guise of helping the North Koreans)

-All of this after a century of foreign enslavement. The UK had practically destroyed the social fabric of the country with opium trade from India. And the various other powers (US, Germany, Portugal, France) were belligerent to the point of seizing Chinese territory.

No doubt there were numerous failures during Mao's years, but it is unfair to attribute all of them to Mao himself. In many cases it was corrupt party subordinates who should be held accountable. I dont think its fair historically to look back and play "what ifs" and "shoulda dones". I think its important to evaluate the intention and consequences of actions based on the realities of the times. Maos decisions make sense in the context of the times, though I will admit that the reality on the ground in many cases was not the same reality that was planned out. So in the end, Mao, responsible for deaths? Yes. Genocidal killing machine? No. Responsible for ALL the deaths? Certainly not.

Its the age old question of do the ends justify the means? Murder to me implies forethought into killing for a purpose. Maos plan was never to liquidate portions of the peasantry, and if they died it was certainly outside of the desires of the CCP.

It is true that there was hunger and starvation although there is no consensus on exactly how many people died. The Deng administration's official estimate is 16.5 million people (in a country of, at the time, 500 million). Others dispute this number, saying it was much, much lower. Many anti-communists estimate it was potentially any number of people above 16 million (I have heard every imaginable number between 16 million and 100 million... okay, not literally, but seriously, there is absolutely no consensus on how many people died, even among anti-communists).

What is needed here is context.

Between the years 108 BC and 1911 there were 1,828 famines in China. This means that in China, before the revolution, there was famine in China nearly every year. But the last major famine on record is the "Great Chinese Famine," the very famine you are asking about, emerging out of the policies of the Great Leap Forward. This is because before the GLF agriculture was highly individualized, land had been parceled out to peasant families to work individually in the revolution. The Great Leap Forward was a process of agricultural collectivization and mechanization/industrialization and marked a basic transformation/transition in the economy of the country.

The famine/hunger happened as this new system was being deployed, and I think everyone agrees that there were at first severe production shortfalls/accounting problems. I would say that the collectivization process was undertaken too fast and that they tried too hard to switch the whole country's agricultural system over too quickly. It was a new system and they should have spent more time figuring out the system before implementing it across the whole country. Many great strides can be taken but nobody would have been disappointed had it taken six years rather than three to transform a country of 500 million's agricultural system. But after this massive transformation had occurred, the rate of famines dropped from nearly every year to... well, the Great Chinese Famine is the last one listed. There may have been one or two smaller famines since, but not remotely like it was before.

The real story here is that collectivization in China ended famine as an annual occurrence and was in that way a huge triumph and anti-communists don't want you to understand the real significance of this, so they zoom in on the initial upsets in production/distribution that occurred (which were preventable) rather than encouraging anyone to look into the long-term significance of collectivization.

For context, more people have died from hunger in the last 10 years than have ever been alleged to have died as a result of the international communist movement in its whole history, but today regularly half of the food that's produced is wasted (ie whereas in China some people starved only because of a temporary absolute shortfall of food, today we have the opposite problem, which hardly sounds any better -- every year there's more than enough food produced by a huge margin, but people are starving in their millions anyways because governments are committed to ensuring capitalists can make a profit off of the food market by imposing scarcity in a situation of objective overabundance).