In September, I received an email that should have left me feeling vindicated.

It was in response to the nonfatal shooting of Levar Jones, an unarmed African-American man, by Sean Groubert, a white South Carolina state trooper. Groubert would later claim he shot Jones because Jones came at him in a menacing way. But this lie was unmasked by Groubert’s own dashcam video, which shows Jones complying with the trooper’s orders until Groubert inexplicably panics and starts shooting.

That video moved a reader named David to write the following: “Think I FINALLY get what you’ve been saying all along. That cop just shot him down for doing nothing more than compiling (sic) with his commands. No offence to black people, but I SURE AM GLAD I’M NOT BLACK IN THIS COUNTRY! Re-evaluating my opinions of the last fifty years.”

As I say, it should have felt like vindication. But it only made me sad. I kept thinking that, had there been no camera to prove Groubert lied, had there been only testimony from witnesses and whatever forensic evidence was gathered, Groubert would likely still be making traffic stops and David would support him, his opinions of the last 50 years unchanged.

My point is not that cameras are a panacea for justice — they weren’t for Oscar Grant in 2009, they weren’t for Rodney King in 1991, they weren’t for Abram Smith and Thomas Shipp in 1930. No, my point is that the bar of proof is set higher when white people — police officers in particular — kill black ones. My point is that rules change and assumptions are different when black people seek justice.

Knowing that, who can be surprised at what happened in Ferguson, Missouri, Monday night? Who can be surprised that a prosecutor who didn’t seem to want an indictment did not convince a grand jury to return one in the August shooting of Michael Brown? Who can be surprised that Officer Darren Wilson now goes on with his life after firing 12 shots, at least six of which struck home, at an unarmed teenager while said teenager remains imprisoned by the grave? Who can be surprised people in Ferguson and around the country convulsed with shock, sorrow and disbelief? Who can be surprised some vulturous knuckleheads saw the calamity as an excuse to break windows and steal beer? Who can be surprised at pictures showing that the “injuries” Wilson sustained in his scuffle with Brown, injuries that supposedly made him so terrified for his life that he had to shoot, amount to a small abrasion on his lip and a reddened cheek?

I’m glad that video helped David to “FINALLY get” what I’ve been “saying all along,” i.e., that a police officer’s mouth, to use one of my mother’s expressions, ain’t no prayer book; no source of infallible truth the way too many of us think it is. And that benefit of the doubt is something black people are often denied. And that America devalues black life. But if we have to go David by David to those realizations, each requiring a dashcam video before he gets the point, we are doomed to a long and dreary future of Fergusons.

Last year, when the thug George Zimmerman was acquitted in the killing of Trayvon Martin, I wrote that black people need to “wake the h—l up” — organize, boycott, vote, demonstrate, demand.

But black people aren’t the only ones sleeping. Too many — not all, but too many — white people still live in air castles of naivete and denial, still think abiding injustice and ongoing oppression are just some fairy tale, lie, or scheme African Americans concocted to defraud them. Or else that these things are far away and have no impact on their lives. The fires in Ferguson Monday night suggest that they continue that delusion at their own peril.

I still think black folks need to wake the h—l up.

But white ones do, too.

Leonard Pitts Jr. is a columnist for the Miami Herald. Readers may write to him via email at: lpitts@miamiherald.com.