Formally Disproving Divine Command Theory

[Neo-Scholastic]

The term "fallacy" generally refers to contradictions within an argument that render the argument invalid. An argument can be valid even if the truth of its premises are in doubt. If we had to "prove" every single premise, all of philosophy and scientific theory would be thrown out the window. FallentoReason is perfectly justified in making his assumptions.

Sounds like you're only defending the structure of the argument. Fair enough. An argument has both a structure and content. The argument is invalid if 1) its structure is not truth-preserving and 2) if any of the premises are not true.