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When white racist Dylann Roof allegedly shot and killed nine people in a black church in Charleston, South Carolina, it was very easy for President Obama and his media enablers to paint with a broad brush and blame the wider political culture. Bill Maher even blamed Fox News and the Daily Caller and the Drudge Report.

But when black racist Micah Johnson gunned down five cops and wounded seven others in Dallas, suddenly the motivation was complicated, and it couldn't be blamed on a "climate" of hostile rhetoric.

Dallas police Chief David Brown reported, "The suspect said he was upset at white people. The suspect stated he wanted to kill white people, especially white officers." His Facebook page had "likes" for Black Lives Matter and the New Black Panther Party.

But in a news conference on Saturday in Warsaw, President Obama ignored that, claiming it was "very hard to untangle the motives of the shooter." It couldn't be blamed on the rhetoric of, for example, Black Lives Matter protesters, who chanted, "Pigs in a blanket. Fry 'em like bacon."

But the media gushed over the speech Obama gave in the wake of the Charleston shooting, as the president hammered home a denunciation of racism. "The fact that this took place in a black church obviously also raises questions about a dark part of our history. This is not the first time that black churches have been attacked, and we know the hatred across races and faiths pose a particular threat to our democracy and our ideals."

Nobody expects Obama to stand anywhere and say anything like that about Black Lives Matter or the New Black Panthers. Shouldn't that alone be a news story?

It won't be, because the same double standard occurs in the media. MSNBC analyst and Washington Post columnist Eugene Robinson announced after the shooting in Charleston, "There's more than a whiff of white supremacy in the air. It's still a stench. It's fainter than it used to be, but it's there. And somehow he breathed it in." Chris Matthews agreed: "I do think you've got something there with the atmospherics. And it's not all one person acting alone, it's always about something that gives moral license to certain kind of behavior."

But after Dallas, Robinson wrote a column that completely avoided Johnson's motives and absolved the Black Lives Matter agitators. "I hope police officers around the nation see how rapidly and completely the people of Dallas -- including those in the Black Lives Matter movement -- have rallied around their city's bereaved Police Department. ... Such tragedy is beyond color."

Likewise, The New York Times editorial board pretended that Johnson's motive in Dallas was an unsolvable puzzle: "In the aftermath, possible motives will be ticked off for the killer and any accomplices. But the police and protesters alike could only wonder what might truly account for such a level of atrocity."

But after the Tucson shooting in 2011, when madman Jared Loughner killed six and wounded Rep. Gabrielle Giffords, the same editorialists wrote it would be "facile" to blame the tea party or the GOP, but "it is legitimate to hold Republicans and particularly their most virulent supporters in the media responsible for the gale of anger that has produced the vast majority of these threats, setting the nation on edge. Many on the right have exploited the arguments of division, reaping political power by demonizing immigrants, or welfare recipients, or bureaucrats."

Conservatives start by blaming murder on the actual murderer, not a "climate." And yet liberals only blame a "climate of hatred" when they can smear it on conservatives. The left's hatred is perennially dismissed as a cause, and not recognized as a blight on our discourse.