It's in some other FR books involving the drow.

Vague spoilers for FR lore that's probably 20 years old below:

Back when the elves had empires which ruled the world (some point after the phaerimm, dragons, aboleths, but before the Netherese), they had a bunch of wars. One elf empire found a balor who was willing to give them power by interbreeding with them. The entire elf empire got forced underground, their goddess ditched the original elf pantheon to live in the Abyss and renamed herself Lolth, and the head of the elven pantheon cursed them all to be black skinned. The word drow comes from an elf word meaning cursed or something like that.

Only the dark elves with the actual demon heritage are unredeemable. The dark elves who descended from ordinary people in the old empire aren't biologically forced to be evil, but dark elf society makes it hard for them to be good.

In one Forgotten Realms series, they do a magic ritual to redeem all the non-demon dark elves, who lost their dark vision and black skin and got to live on the surface with the other good dark elves (because there's a whole society of them, it's not just Drizzt).