An excellent point. Seems a little less likely, though, to be propaganda when the purported perps proudly and gleefully post the evidence of their crimes.
As if the Nazis had provided live internet feeds from Dachau because they were so proud of what they were accomplishing there.
In actual fact, of course, the Nazis went to considerable pains to keep what was going on in the camps as secret as possible.
Perhaps the act itself is being used as propaganda. Somebody wants Christians, Jews and Muslims to wipe each other out. They want a religous war.