Yeah, this is the fundamental disagreement. When discussing morality, I'm not talking about what you are. It is a law that overrides all of us, with true right and true wrong. Without a monotheistic God, these don't exist and morality doesn't either.
The morality your discussing is completely different.
Morality is “rational” as a solution to a game theoretic problem. You can also derive it via evolution (which is also a game theory solution).