Veterans writing only stories about veterans for veterans. I think one can imagine oneself into another person's life. I think that we owe it to ourselves to check our perceptions. So, if I'm writing about foster kids experiences, I talk to people who have been foster children and listen to their experiences. I think artists are here to appropriate the stories of the world.
Most writers are shy people who experience life very internally.
If I tried to write my personal experience it would be the dullest story known to man, whereas people out there living exciting, complex lives don't usually write about it. One of the pleasures of White Oleander is observing the development of Astrid's aesthetic and cultural palette as distinct from her mother's. Ingrid's sensibility is given whole to the reader from the start.