And yet, it is always and only implemented with violence. Must just be bad luck. Oh! Or it's not "true communism", how about that one? That was "stalinism" instead of "communism" (and Germany was under "hitlerism" not "nazism").
Hitlerism and Nazism are the same.
Nazism was specifically implemented in Germany between 1933 and 1945. Racism and genocide are necessary parts of nazism. It is also very warlike.
Communism, meanwhile, was tried in a number of countries at various times. Communism refers to a much greater variety of ideologies. Most of them were not particularly muderous.
Some communist regimes killed millions in pursuit of their ideology. For example, the cambodian, 'red Khmer' murdered about 25% of the countries population largely out of hatred for urban, liberal elites. The terror of the red Khmer was ended by an invasion by communist Vietnam.
The main thing that makes nazism seem especially horrible is that people were killed for things beyong their control. If you were descended from jews, they want to murder you and there is nothing you can do about it.
Even the most murderous communist regimes would try to kill you for things you might be able to control and allowed for redemption (at least officially).
Most of the death toll attributed to communism is due to famine. Famines were caused by ideologically driven mismanagement.
But mostly, the communist countries were just dictatorships. Like other dictatorships, or monarchies, they cracked down hard on dissidents but did not get millions killed.