Explain how "leftist" and "totalitarian" are the same thing.
No one ever claimed they were. That is why there are two separate words in the dictionary.
Good answer. You put a lot of thought into that, didn't you?
I'll rephrase it: How can a government be both "totalitarian" and "leftist" when the two philosophies are completely opposed to each other?
Evidently they figure it out somehow. Do you want to go down the list for the 20th century? We can start with Pol Pot and work our way out.