I don't know about blue, but I've had experiences of Jungle fowl that hated yellow.
When I was a teenager, I was a Zoological Explorer Scout, and worked at the Seneca Park Zoo, in Rochester Ny. They had Jungle fowl running around the area where the large hoofed animals were kept. They were completely peaceful, benign birds
until I put on the yellow work boots we used before cleaning the enclosures. Those yellow boots sent the roos into a rage! I'd be raking and hear the slap, slap, slap, of angry little chicken feet running up behind me. They would jump up and try to sink their spurs into my upper legs! Take off the boots, and they went back to being calm, serene birds!
I think maybe that the yellow boots mimicked the bright yellow of another rooster's legs, and triggered aggression. At least that is my theory. Is your roo an Ameraucana or EE? The have blue legs, so maybe he has the same issue?