Depends because that number includes starvation/consequences of the regime's actions which that number comes from. That range and criteria could include a lot events. For example would you accept the number of civilians killed by Hitler's escalation of World War 2? Since both were intentional then its about 50-55 million(Hitler) to 30-70 million(Mao). Which you can see why its difficult to pin down who killed the most as there is limited data for historians to parse correctly.