While the Nazis and the Communists certainly weren't identical in their evil (I'll grant you that), how about comparing the Nazis, the Communists, and the liberal democracies of Western Europe -- and, when looking at it through that lens, the Nazis and the Communists are, for practical purposes, nearly indistinguishable relative to those democracies.
There is not so much a left-right spectrum (with the left being the polar opposite of the right) but, instead, more of a circle where the extreme Left merges into the extreme right (and liberal democracies are 180 degrees away on the "other side" of the circle.
You need to read some histories of capitalism and imperialism by people who don't admire it.
"When capital and the ruling classes apologise for: Colonialism, the 14 hour day, class privilege, the 7 day working week, children in coalmines, the opium wars, the massacre of the Paris Commune, slavery, the Spanish-American War, the Boer War, starvation, apartheid, anti-union laws, the First World War, Flanders, trench warfare, mustard gas, aerial bombing, the Soviet Intervention, the Armenian Genocide, chemical weapons, fascism, the Great Depression, hunger marches, Nazism, the Spanish Civil War, militarism, Asbestosis, radiation death, the Massacre of Nanking, the Second World War, Belsen, Dresden, Hiroshima, Racism, The Mafia, nuclear weapons, the Korean War, DDT, McCarthyism, production lines, blacklists, Thalidomide, the rape of the Third World, poverty, the arms race, plastic surgery, the electric chair, environmental degradation, the Vietnam War, the military suppression of Greece, India, Malaya, Indonesia, Chile, El Salvador, Nicaragua, Panama and Turkey, the Gulf War, trade in human body parts, malnutrition, Exxon Valdez, deforestation, organized crime, the Heroin and Cocain trade, tuberculosis, the destruction of the Ozone Layer, cancer, exploitation of labour and the deaths of 50,000,000 Communists and trade unionists in this century alone, then - and only then - will I consider apologising for the errors of socialism."