Who is it racist against? Surely it's white people primarily who suffer as they're more likely to be caught by the facial recognition?

Following the simplest case, because lighter skin gives greater contrast is _not_ racism.

It's not 'unnecessary discrimination' either, as it arises out of the facts of how light works.

It's like saying that products with a weight limit that arises out of the materials used are "fattist".

I don't think you understand how light works.

You better explain it to me then. I'm not great on QFT, so keep it graduate level physics so I can follow along.