An Argument from Moral Realism to Atheism

In a recent article, Quentin Smith formulates a creative argument for atheism based on the combination of moral realism and infinite spacetime. Smith formulates his argument as follows:

1. Moral realism is true.
2. The universe in which we live is infinite.
3. At least one relevant version of an aggregative theory of values is true.
4. Therefore, God does not exist.