Not even to defend Mao, but the “X bajillion dead” numbers come from the black book of communism, which is an extremely dodgy source with really dubious ways to get the highest possible number.
It’s an ideological project that deliberately ignores people dying from hunger in countries exploited by the West (millions per year) to pretend that China under Mao was objectively the worst country ever.
That’s not to say that he’s defensible (I honestly don’t care if he is), but rather that your basis for that specific criticism is literal propaganda published for the benefit of Western moneyed interests.