And he gets a damned sight more of my sympathy than the torturers do when things go "wrong", not that anyone cares for my sympathy. As for the skills and risks involved, I have been at a rodeo once, where I was far more impressed at some of the skills, and the care taken for the animals' well-being, but bull-fights...!

You are quite correct about the flags. Watch the matador carefully; he stands dead still and moves only his cloak. Moving more conspicuously than the cloak could be deleterious to his well-being.  There is nothing special about red as far as the bull is concerned, because cattle are colour-blind. A white rag is more effective, reflecting more light and therefore being more conspicuous.