Earlier quoted context omitted.
China has definitely become much better on human rights. It's not often mentioned in polite company, but the Chinese communist government killed ~65 million of its own citizens under Mao. I don't want to downplay the current regime's many and serious human rights violations, but they are thankfully on a much more modest level. Internationally, China has focused strongly on peaceful trade, not military confrontation.
They didn't kill them. They went through a government change, a revolution where they were experienced in fighting, not farming. The alternative was living under the old government that they hated. It's like in Zimbabwe, they kicked out the white farmers and suddenly they're no longer the bread state.
There was plenty of that, but it's not the dominant factor: https://www.heritage.org/asia/commentary/the-legacy-mao-zedo...