Also, these lines:

"Browns and yellers, all have fellers,
Gentlemen prefer them light"

reflect Black people's color prejudice against dark complexioned Black people.

and the line "I wish I could fade" means that the singer wishes that she could pass for White, but she's too dark to do so {she "can't make the grade"}.

That end line of that verse "Nothing but dark days in sight" reinforces the black=bad theme of that entire song.

I don't think that the "what a bright world this would be" line in "One Candle" is the opposite of "Nothing but dark days in sight".
The "bright world" in "One Candle" expands on the "light a candle" to rid the world of darkness theme. "Darkness" in the One Candle song represents to me the evil that is done in the dark.
"Darkness" in "One Candle" song isn't tied to skin color as it is in the "Black & Blue" song. From beginning to end that "Black & Blue" song disses Black people simply because we are Black.

And that "I'm white inside, It don't help my case/'Cause I can't hide, what is on my face" line.

Terrible!!!!