No not dragged (bad headline). But he is being yanked by the arm by some guy out of camera range. That guy was obviously not trying to help (unlike the guy with the phone in his mouth).
Somehow, Toby Harnden already saw and was able to get published a story on the footage hours ago, but we’ve still not seen it yet—you’re entirely right.
“Footage of the body of Christopher Stevens, United States ambassador to Libya, slung over the back of a protester, was reminiscent of the 1993 ‘Black Hawk Down’ incident in Somalia in 1993 when militia fighters lynched American aircrew in the streets of Mogadishu.”