A few random examples:
* Ottoman genocide of Armenians, on ethnic/religious grounds. The Ottoman Three Pashas regime was as far from left as possible, but plenty totalitarian.
* US internment of "foreign elements", including those with US citizenship, during both World Wars. US was never even center-left, let alone farther, and totalitarian is a stretch. Less bad than the other examples here, but still.
* The many White and Red terrors in the Interwar and post-WW2 years, where vague association was guilt and execution.
* Of course Jews, Roma, Gypsy, dissident in Nazi concentration camps.
* The Herero and Namaqua genocide by the rightist totalitarian-ish Imperial Germany.
* UK mass internment of Boers. Not leftist, not really totalitarian.
Need i go on? Why did you feel the need to pain totalitarian leftist as worse than any other totalitarians?
Unless that information makes the statement seem extremely biased, which it does?
> During the 1900s the left killed people on a scale never seen before in human history
And during the 1900s totalitarian rightist killed people on a scale never before seen in human history. Industrial murder factories, with brutal precision, murdering thousands per day by the trainload, with an assembly line of transportation, robbing, murder through poison gas, cremation? Never has humanity sunken so low. Brutal ad-hoc genocides of people murdering another group with their hands due to hatred or misinformation or whatever is more understandable and explainable than cold blooded mechanised precision mass murder on an industrial scale.
Famines due to ethnic cleansing, stupidity, mismanagement and ignorance are aplenty. The Bengali famine is comparable to the Holodomor in scale and reasons, even if the Holodomor was probably more intentional. Nobody has done what the Nazis did at that scale.
So yes, it's extremely stupid to single out totalitarian leftist regimes for their crimes against humanity, as if it's a uniquely leftist thing. It's obvious the people doing that have an anti-left agenda, which is honestly just being stupid.
I wonder why you feel that it is necessary to attempt to be insulting?
You chose to ignore that, blathering on about the middle ages is off-topic.