“It’s like poetry. It sort of rhymes.”
Regarding the lightsaber colours, I have studied colour theory and the opposite of red is green, not blue. Orange is the opposite of blue. I suspect this because Star Wars is an American property, and because red and blue are the primary colours of the United States of America, Lucas settled on blue for the good guys and red for the bad guys. In fact, Luke’s RotJ lightsaber was originally going to be blue, as evidenced by the trailer, but was changed to green as it would stand out better against the blue sky.
I think the choice of red and blue mostly has to do with the preexisting connotations of each color. Red is the most primal color. It’s the color of blood, fire, and anger. While blue is a more ethereal color, much less common in nature, that’s associated with water, sky, and serenity. It was definitely a deliberate choice to pit a very carnal, visceral color against a very soothing, spiritual color.