Space aliens would be hard pressed to slaughter 70 million human babies, or 50-100 million Chinese, or 30 Million Ukrainians, or 6 Million Jews, etc., etc.
I agree that communism is a threat. But it isnt directly a threat to all human life. It is a threat in that it slows our technological progress which, in turn, makes us more vulnerable to something more deadly.
Mohammedism...