That's not true. We get nefarious people who grow up thinking they don't have to answer to anyone about the awful things they do when we remain silent. We get people like Harvey Weinstein or George Epstein; these two men didn't have to answer to anyone for a long time because everyone around them were too scared or too complicit to say anything. I know that's a jump, but the mindset is there.
The black parents are wrong for the racism committed against their son? That thinking is no different then saying certain people deserved to be robbed because they dare to dress nice and wear jewelry. At some point people will have to decide if white racists need to change or black people have to accept that they'll always be judged for the color of our skin. If you think about it, even if you teach your child the ins and outs of racism, will that omit them from being a victim of racist behavior? We can be responsible all day, but that's a band-aid. The root of the issue is white people who refuse to change their ways and pass that onto their descendants.
White people aren't going to change their ways my friend. Not the white people who count. Sorry to bust that utopian bubble. And why would they? In their minds, to "change" would be risking everything they've fought and died for since before this country was officially founded. White people have a system designed to identify and train those who will uphold the system of white supremacy into the future generations.
The tone of your thinking is that of someone who sees himself as inferior. White people don't have to change for Black people to understand who we truly are and what we're capable of doing, in every facet of society. Teaching my child the ins and outs of racism, while instilling in him his own history and a strong sense of self will teach him how to deal with racists when he encounters them. Instead of trying to squeeze into white spaces and conforming while accepting all manner of abuse and hoping the racists around him will "change," or some other benevolent white person will step in and speak up for him, hopefully, if I've prepared him properly, he'll work to create his own space. Failing that, he'll at least find a healthier environment with a better group of people.
The Black kid in OP's post didn't have to hang around those white kids and take their abuse everyday, and at a certain point there should've come a time where he said enough is enough. Not saying he had to be Nat Turner, but he could've found a different group of people to hang around. So yes, I'd have to question the job his parents have obviously failed to do.