Let me ask this then
Are valuations of things, like, say, chopping off little children’s arms, basically neutral? There’s no underlying sense of what is good and what is evil, that is shared across all humanity? Or if there is, where the heck did that come from?
What survival advantage led selflessness, or abhorrence of the torture of innocents, to an evolutionary advantage?
Apologies to C.S. Lewis, ‘Mere Chistianity”
Given that the Bible authorized the Jews periodically to wipe out other ethnicities, I would say that if you want to make the case for evil being relative, the Bible is more useful than not.