Hitler was a bad dude, but I will make arguments for each of these horrible people besides hitler. This will obviously take several answers.
#1: Mao: he killed at least 40 million Chinese people, possibly even 100 million. He ordered that anyone speaking against him should be publicly humiliated or executed, and he forced everyone to read his “little red book” (which some Chinese still have today) full of propaganda to brainwash the people to think his way.
#2: Stalin: he killed 20 million Soviet people, putting even more salt on the wound of 27 Million Soviet Deaths in WW2. A lot of the USSR countries still have not recovered from Stalin’s stupidity. He was also partially responsible for some famines, causing cannibalism among the people. Stalin also gave Kim il Sung (the North Korean ruler at the time of the Korean War) even more support in the Korean War, and possibly contributed to the start of it.
#3: Hideki Tojo: many many many many MANY people overlook the Japanese war crimes in ww2. A lot of these crimes cannot be mentioned here; they are literally that bad. Although the Japanese have moved on, the crimes they committed against the Chinese People, Indonesian People, the Filipino people, the Australian military, the Indian Military, the Thai people, the British Military, the Dutch Military, the New Zealand Military, and finally, the U.S. Military. Almost all of this was Tojo’s fault. He supported war crimes, he supported killing innocent men, women, and children, and he supported the complete genocide of almost all of non-Japanese Asia.
#4: he is about the same as Tojo, but he has less power. Hirohito can also be blamed for the numerous war crimes of the Japanese, and he signed off on using chemical weapons against the Chinese civilians. He is pathetic, and he is responsible for millions of good people dying.
#5: Ho Chi Minh: leader of North Vietnam. He invaded South Vietnam to reunite them under one Vietnam. Although not as bad as Mao or Tojo, he committed numerous war crimes against the South Vietnamese people, the South Korean Military, the Australian Military, the New Zealand Military, the Filipino Military, and the U.S. Military. He forced innocent villagers to betray American soldiers, causing even more bloodshed in the crossfire the villagers were in.
This is obviously too long so I will do a second one. But this is to convince you that Hitler wasn’t the only person that had a premium seat in Hell.
