In every country there are military bases etc in civilian areas so that's just a non reason.
However, no proof it was weapons being detonated, there were explosions and lots of fire. The IDF dropped the bombs, and they done the investigation, that should tel you all you need to know.
This could have also been from gas stoves. Remember the area that was targeted was a designated safe zone where displaced civilians were sleeping in tents, they'd use these stoves to cook what they could. I think this is more likely the cause of the explosions (other than the actual bombs that were dropped).