If I'm reading this correctly, I believe that you are mistaken. Just find any group of small children playing together from mixed ethnicities and you will see that they could give a hoot about race. As a child, I can't ever remember having "racial thoughts". The Civil Rights movement and Brown vs BOE decision were the big news factors.
You are correct that PARENTS who have strong racial bias are the culprits and fill their children with all sorts of hateful thoughts--and so do parents with extreme religious ideas. The Ministry of Parental Propaganda is in full tilt.
I just read something in the TIMES from the census that about 20% of marriages are now mixed. BUT, there is still a lot of racial bias in the land, and it is not lkely to ever go away--for many reasons.
Crossdressing is never going to be mainstream so we just have to reconcile ourselves to that fact. Besides, children don't have to know everything. Parents or adults are allowed to have a private life and maybe it should be that way. In the last 30 years or so, the tail has been wagging the dog anyway--children now control so much and parents tend to give up their parenting roles. Children have some rights, but there still need to be adults in charge.