Ya,why the heck is that. Why put something into your soda that will stain clothes, carpet, pets, for no reason. Big Red is also Red, but Shasta Creme Soda is clear. What part of cream soda implies red. If you have red creme, something is really, seriously wrong.
Barqs Creme is sometimes available, A&W Creme Soda is more common.
I think I read somewhere once that red is a stressor color, which can induce or increase hunger and thirst. So that might have something to do with it. Or maybe they felt that the natural color of the drink was unappealing somehow.
Or maybe they're just in cahoots with stain removal product companies.