You make at least three significant mistakes.  First, you say:  "Every time one mentions some crime done to Black people, the response offered is that they deserve it."  That's not even close to true, nevermind an acceptable minor overstatement.  This country is still rather conservative, and certainly I spend most of my time in conservative circles.  But except among the most virulently racist, I never hear anything close to "they deserve it."  

"Families would be strong, if the parents were proper parents."  You say this as though it's ridiculous to believe it.  It's not.  In fact, it's generally true, which is why we try to raise children who will model on good parents.  In general, proper parenting leads to strong families.  

"What were the actual harms of Plessy v. Fergusson, and in what sense were they materially made right by Brown? (They weren't.)"   Wrong.  The actual harm of Pleassy was that the law itself allowed discrimination against Blacks.  Now, after Brown, 
cont'd