I know too many black women who have receding hairlines, severe hair breakage or who have gone bald as they got older due to alopecia. Usually these things are caused by harsh chemical relaxers or too-tight cornrows or heavy hair extensions.
Like the blogger, I had always had very thick hair, and it had been thinning and receding after years of using chemical relaxers. My main reasons for choosing to go natural were because of my concerns about what the harsh chemicals and toxins in relaxers were doing to my body and the environment, and to set an example for my daughter so she would know that her natural hair is beautiful.
Going natural seems to be spreading, at least in my circles. My sister, my college roommate, and the mother of the only other black child in my daughter's daycare, are all people I know who have gone natural in the last few years. And as the Black Snob notes, it's not really a political statement. It's about embracing our natural beauty, saving our bodies, saving the environment, and yes, saving our hair.