As for "I have been shocked and saddened by racial incidents I had thought were in the past and unconscionable in the present", not sure why you would expect that. Such unacceptable incidents have been happening all the time, including in other countries. I have certainly been well aware of it, including now.
Having lived in the South most of my life. Even while in the service I was stationed in places like my home state of Texas, Mississippi, Alabama, even Southern Thailand (ðŸ˜), in a era of great racial turmoil. But when I checked into a motel while traveling through Alabama and the attractive black woman manager of the motel was sitting at her desk companionably sharing a cup of coffee and conversation with an older white man I knew to be a retired police officer, I said to my wife, "the civil war is finally over". It was a scene that would have been unthinkable even a few years earlier. Yes there were still occasional clashes, but they were primarily cultural not racial. Obviously I was wrong.
If there is a single entity to blame for the resurgence of intolerance I think it would be social media. It is where groups of like-minded individuals can congregate and effectively shut out or shout down any opposing voices and convince themselves they are the great majority because theirs is the only opinion they hear. As a champion of free speech and a dues paying member of the Electronic Frontiers Foundation, I believe that even racists and misogynists have a right to be heard, but their right to free speech does not give them the right to shout FIRE in a crowded theater or openly plot an insurrection. We need to convince them their hateful actions
WILL NOT DO.
