Earlier quoted context omitted.
People drastically understate the infrastructure and other issues you note in places outside of major urban centers of technology. My children do not have a net benefit from a huge home on a huge plot of land if the schools are garbage, there are few or no parks, the politics are very conservative, and diversity is lacking.
As someone coming from Poland, a country that’s pretty much 100% white and Polish, I don’t feel that the lack of “diversity” has negatively impacted my development. It seems to me that people in the US have been brainwashed (in schools, by media etc.) into believing that diversity is always good and lack of diversity is always bad, while in reality it’s not that simple.
They said they want diversity for their children. That has nothing to do with how your environment impacted you. People are allowed to have preferences so long as in the process of acting on them, they don't trample on others' rights.