I'm curious about the historical origin of this trope and where it comes from. I know it has to have evolved from somewhere in history.
I know different cultures have different colors for their beliefs in alignment. For example; the Japanese believe that darkness and evil is often associated with the color purple, but in Western society historically purple was often considered royalty.
TLDR: I want to know why historically the color blue and red are often associated with the colors blue and red.
Is that really a trope ? Even by putting aside the vagueness of "Western Culture", I don't really see much exemple of that color coding, at least not in the clear way "Blue =Good, Red=bad". White and Black, yes, but red and blue ? Do you have exemples ?