I'm afraid the question contains two false assumptions:
Atheism isn't an institution; it's the absence of belief in gods.
History doesn't really show that it brought forth totalitarian governments; what it does show is that totalitarian governments often fear the church and will try and weaken it and (in the examples you gave, and particularly in North Korea and Iran) replace religious belief with worship of the political leadership.
Some did and do, others didn't and don't. Hitler attacked atheists as he seemed to equate atheism with communism.
Some totalitarian regimes fear the church and try and suppress religious beliefs (probably to try and make the population worship the political leaders).
Atheism, as a belief system, does not inherently dictate a specific system of government. Atheism is the lack of belief in a deity, and individuals who identify as atheists can hold a variety of political beliefs and support different systems of government, including democratic, socialist, or authoritarian systems. Atheism itself is primarily concerned with questions of religion and does not necessarily define one's views on governance.
Atheism is a noun.
Atheism is the belief that there is no god.
There are no prophets of atheism.
George H. Smith has written: 'Atheism, Ayn Rand, and other heresies' -- subject(s): Atheism, Philosophy, Religion and state 'The Wealth of Nations Part 1' 'Why Atheism?' -- subject(s): atheism 'Atheism' -- subject(s): atheism, Atheism, Controversial literature, Christianity
Atheism is not a religion. [S] [V] [o] Here you are, a complete sentence with atheism.
"Atheism is not a religion."
Atheism is the lack of belief in God.
Atheism was never established, as it is not a religion.
Atheism is by definition not a religion.