Why does a bull react violently to the colour red?

It is the movement of the cloth that makes the bull react violently as like most mammals, the bull too is colour blind and cannot be affected by the colour of the cloth. When a matador moves a cloth (irrespective of the colour) in front of the bull, it perceives the movement as a threat and is angered, and as a result, reacts violently.

Bullfighting, Movement of the cloth, Bull reaction, Mammals, Bull, Colour blind, Matador, Violent reaction