Show me any writing from Marx or even Engels that advocates genocide. You're confusing authoritarian despotism for Communism.
Gee, how could I do that? It wouldn't be because every Communist government in history has been run by an authoritarian despot, would it? And I can see that same angry attitude among leftists in the Canada. They're so damned certain that what they want is for the betterment of mankind, especially the downtrodden, that they are infuriated at anyone who opposes their policies. After all, if you want to do something which will be a wonderful thing and help the downtrodden, and someone opposes that, why they must want to
hurt the downtrodden! That makes them evil! Enemies of the people! And what happens to enemies of the people when the revolution comes?
It takes a bastardization if Marx or complete ignorance of his historical observations to even remotely proclaim that the purpose of Communism is to "slaughter millions."
But the Nazis will tell you their policies are for the betterment of mankind, that getting rid of defective elements will improve the quality of the species and society will be more enlightened and more peaceful, with less crime and everyone working together. Wouldn't that be nice!?
The purpose of Communism is not to slaughter millions. That's just the way it always seems to work out. Enemies of the people can't be allowed to stand in the way of forming a more perfect society, after all.