Man, that's some bullshit. My wife grew up as a Korean adopted into a white family in Colorado Springs. I'm white, grew up in Spring, TX.
I'm sure we have it easy compared to other mixed race families, with our little one being light-haired and light-skinned. I know my wife dealt with plenty of racist shit growing up though. I got to experience some in-your-face racism when our cars and driveway got vandalized while living in Decatur for 18 months.
I never gave a thought as to where I would feel comfortable raising a family until the last few years. I'm so sorry your daughter has been made to feel unwelcome where she lives and goes to school. The Houston suburbs seemed liked a great, albeit boring, place to grow up as a white boy. As an adult, I see my parents and the friends they surrounded themselves with, and know that my hometown is not where I would want my kid to grow up. I just hope Round Rock ends up being a good place for our little guy.