A mage may not wish to possess her powers, but neither does a poor child wish to starve in the streets, or become a thief or a killer to survive. One must always hate the sin, but love the sinner. All of us are in some way victims of circumstance, should that be the way one chooses to view the world. Isn't it possible that even the meanest of lives has some meaning, some sort of greater purpose? A poor child may choose the higher path, despite the hardship, to find some way to pull himself from the dust and better his community. The mage may rise above her circumstances to protect her country, and someday save scores of lives with her magic.
It's impossible for anyone to chose how they are born. We all must seek to do the best we can in life with what we are given, even if what we are given is the sin of magic.