The fact that the Commandments are written doesn't prove that God is the author. There is no crime or moral offense that has not been committed by people claiming to be believers. There are few categories of crimes that have not been committed in the name of God. The Bible itself states that God ordered the Israelites to commit genocide.
Bad people do bad things. Sometimes they take the trouble to construct elaborate rationalizations and justifications. Thes justifications sometimes invoke science, but often invoke religion. In either case, it is just a bad person trying to wiggle off the hook.
If you want to pile up bodies, your stack is way, way taller than mine.