Micah Johnson killed those Dallas cops with a gun he bought off Facebook. What must Gersh Kuntzman be thinking now?

Micah Johnson never balked at the $600 asking price for an AK-47 assault rifle. The buy was arranged via Facebook, and consummated in the parking lot of a Target.

Seller Colton Crews forgot about the deal until last week, when ex-Army reservist Johnson killed five Dallas police officers — and federal investigators tracked Crews down.

“I don’t even know how I feel about it right now,” Crews told the Daily News. “I have no idea. It’s awful. It’s just bad.”

Facebook and Target, worse than the gun nuts ever dreamed of being.

What must the conventional be thinking? Soldiers are supposedly heroes. Cops are murderers. Blacks are victims. Facebook is anti-gun. Target is … whatever. This whole story has gone topsy-turvy.

Crews and his step-father remembered meeting Johnson at Target and his being a veteran. At least they thanked him for his service.