White flour has a bad rep.
The life of white flour (basic version):
White flour comes from wheat, but wheat is not white. Think of a wheat field ("For amber waves of grain..."); yeah, so not white. So to become white, the flour goes through a process (hence why it is processed) that strips it of almost all of its nutrients- the bran and the germ. Then it gets bleached and some other technical things, which makes it white and fluffy and therefore more appealing to us, the consumers.
Not over yet. Then, the it becomes enriched which means they add some synthetic nutrients back in but nothing in comparison to the nutrients it had before being processed.
Whole wheat flour and other whole grain flours are different in that they keep their bran and germ and are not nearly as processed as their white counterpart. A lot of people who want to lose weight (for example those trying the South Beach Diet) cut out simple carbs like white flour -the quintessential simple carb- because your body does not feel as full when you are eating white flour in comparison to whole wheat flour.