As a (paraphrased) tl;dr:
We [Americans] were the least racist generation for decades, and even then what little racism remained was on a steady decline on the whole in society.
We have Black idols in the forms of singers, actors/actresses, celebrities, politicians, rappers, and prominent public figures.
We lowered our guards, embraced Blacks as just Americans and our friends/family without seeing the colour of their skin, and we judged them as people/their character as we would anyone else... and then they collectively stabbed us all in the back.
On the whole, they proved the stereotypes that our racist great-grandparents used to rave on about around the Thanksgiving Table, the people we used to roll our eyes at and put up with as they had diatribes, completely correct.
Those relatives are probably eating crow, right now.
And now they're wondering why racism against Black people is again rising dramatically; why people are now viewing Black people on the whole so negatively as they were decades on decades ago, despite supporting hypocritical groups like Burn, Loot, and Murder as they go utterly apeshit in cities; questioning why there's such a wide divide growing again, despite their "attempts" at forcing "equality" (aka anti-White racism).
They're like toddlers who stick their hands on a burning coal, scream in pain, and then stick their hands back onto the coal, confused as to why they're burnt/in pain.