Is 'activist' code for enemy spokesman?
This sounds more like enemy propaganda than an eyewitness account. How many normal witnesses identify as an "activist?" If it is the enemy the person talking to the media is trying to cover for a bad loss and hopes to make the US military pause in its attacks to study what happened The release of the photo with the mosque still standing suggest the statement enemy propaganda. It is similar to other stories earlier in the war that claimed the US was bombing "wedding parties."
The Pentagon said the building in Syria was hosting Al Qaeda operatives when it was bombed. Activists insisted that civilians were killed in the strike.