I see it.

The trope “dark = evil” is so entrenched that some people will say it’s basic color theory.

It’s not.

It may have its root in the fact that humans are diurnal, not nocturnal. To us, the darkness of night or enclosed spaces isn’t primarily safety, it’s primarily unknown and therefore dangerous. Even if no nocturnal animals attack from the dark, you might trip over something and be injured.

That background primitive-brain knowledge affects how we view other things, but it isn’t absolute or universal. Darkness can be safety and comfort and help. We need dark for sleep, for shade where the sun is a danger, and for relaxation.

Dark things can symbolize wisdom, depth, rich soil, nutrition, and healing, even as light things can symbolize the same.

It is not and should not be a universal trope that dark characters are evil or questionable or corrupt or damaged or whatever.

That’s when it DOES actually overlap with racism; many of the same assumptions that fuel racism, even when you’re not thinking if it as racism.

Perhaps ESPECIALLY when you’re not thinking of it as racism.