Moral terms do multiple things, they don’t have a single definition. As a result most arguments are true as intended, and untrue as interpreted.
Atheists have coherent conceptions of “objective morality”. However theist conceptions differ. Thus theists are correct objective moral values don’t exist without God, and atheists are correct that they do. Other atheists correctly claim they don’t exist even if God exists.
The argument thus is about the correct conception of objective morality, not whether there is objective morality.
I use ‘wrong’ to refer to things which harm human welfare. John Rawls uses wrong to describe things rational bargainers would not agree to from behind a veil of ignorance.
If the Nazis won rational bargainers behind a veil of ignorance would still disapprove of them. The holocaust still would have caused harm on net. Obviously majority belief cannot affect this.Claiming “if we had evolved otherwise different things would be wrong” is simply not using ‘wrong’ how either atheists or theists use it.