That makes no sense at all.
Things are done out of positive motiviations. And not "positive" in the sense of good, but "positive" in the sense of an ideology with "positive claims". In the case of Stalin, that ideology was communism.
Not all communist states were/are atheist. Italy's stab at it certainly wasn't.
Benito Mussolini was very much a socialist/communist before going all fascist on us, and while he spouted atheistic
Bennito Mus. When it does include anti-theism, then that becomes part of that 'positive' statement of ideology.
Look....'theism' as a whole includes all forms of theism. Certainly atheists insist that even if one type of theism ignores/is against all other types, and even if a theistic government honors/enforces one type of theism over all others, it is still theist.
By the same token, any government that enforces anti-theism is atheist...even if it isn't a form of atheism you approve of.
Atheism is not an ideology, nore is it a collection of positive claims.
Theism is not an ideology, nor is it a collection of positive claims...but it certainly INCLUDES all theistic ideologies and their positive claims, and so does 'atheism.'
You can't throw "strong atheism' or 'anti-theism' out of the 'atheist' club just because you might not agree with either one.
Communist leaders are dictators who demand 110% loyalty of their subjects. Religion is a threat to them. Not because of their atheism, but because theists tend to put their religion before anything else.
Anti-theism is a form of atheism. You might not like it any more than I like pagan head shrinking human sacrificers...or Westboro Baptists, but they are theists and a form of theism, just as 'communist leaders' (not all communist leaders...just the antitheist ones) are atheists and their anti-theism is a form of atheism. You don't get to commit the 'no true atheist' fallacy any more than I can the 'no true Christian' (or 'no true theist') one.
When a theist is put with his back against the wall having to choose between his God and the communist dictator - chances are big that they'll choose for their God. That is something that such a dictator can not allow. That's why they oppose theism. Not because of atheism. But because of their political ideology: they want their subjects to worship them - not someone or something else.
I'm sorry, but if said leader claims that there is no God, and that his/her actions against theists are because, since there is no God, it is wrongheaded and governmentally fatal to believe in one, THAT IS ATHEISM. Not ALL atheism, but certainly a subset of it, no matter what ELSE that leader is.
You know, just like the leader who claims that there IS a God, that s/he speaks for God, and it is wrongheaded and governmentally fatal to believe in anything else....is a subset of theism. Not all theism, but a subset? Absolutely.
Sorry about that, but you cannot get around it.
That has nothing to do with atheism and everything with an ideology, in this case communism.
An ideology which includes anti-theism, which is a subset of atheism.
Atheist leaders who are NOT anti-theist are called 'secular' leaders. Secular leaders may be atheists personally, but they leave religion (pro or con) out of the government.
Remember, however, that Marx really disliked religion; communism which refers to Marxism is anti-theist as a rather important part of that ideology.
Not all communist ideologies are atheist; some are based very much in theism. The early Christians, for instance, practiced a form of communism. In the 18th and early 19th century the Mormons had the 'United Order," separate communities within the greater system which were communist in nature (the US personal income tax destroyed that idea) and there are certainly communes now which are based upon/included some religious thought.
However, the nations and leaders which were the nastiest and most murderous (Stalin, Mao and the like) were absolutely anti-theist. It was a basic aspect of their governments, and anti-theism is a subset of atheism.
Do not commit a fallacy of composition here; you know the one....that if the whole doesn't have a specific quality, then none of the parts do?
It's the backside of the 'no true Scott' fallacy.
If one subset of atheism is anti-theist, it doesn't mean that all atheist (or atheism) is anti-theist.
Just because ALL of atheism is not anti-theist, it doesn't mean that anti-theists are not atheist.