red colour means La Roja, I mean, the colour of spain in international competitions, specially there is this fever with "La Roja", the nickname of the spanish national football team who has won the Eurocup and now the Wold Cup.
That's why, the organisers decided to change and find a colour which is meaningfull.
Red is also a colour that can be identify with the other spanish national event: corrida
In fact the original jersey was designed by trendy-fashion designer Custo Dalmau, and the red featured black marks as those of a tiger, lion, etc. In fact the spanish feline "gato montes". I find the jersey awfull with those black marks, anyway the organisers decided to make this awfullness more softly and now the red looks just red, which is straight and I like it.