Religion is not theism.
Theism is belief in a deity. There is theism without religion and there is religion without theism.
Religion is a system of law.
Religion is 'to bind' (Latin, religae) or 'law' (Arabic, din).
Religion is often secular.
Jainism, Statism and more are systems of law without deities.
Religion is often compulsory.
What good is a law that can be safely broken? Although separation of Church and State took the guns out of Church, the State's law is still enforced with violence.