You need to check your facts and your baises. There were never any weapons being picked up by the van nor did they ever "appear" to do so. The talk of weapons where wishful thinking because they were so set on engaging:
06:33 Come on, buddy.
06:38 All you gotta do is pick up a weapon.
06:44 Crazyhorse this is Bushmaster Five, Bushmaster Four break. We are right below you right time now can you walk us onto that location over.
06:54 This is Two-Six roger. I'll pop flares [drop flares]. We also have one individual moving. We're looking for weapons. If we see a weapon, we're gonna engage.
07:07 Yeah Bushmaster, we have a van that's approaching and picking up the bodies.
07:14 Where's that van at?
07:15 Right down there by the bodies.
07:16 Okay, yeah.
07:18 Bushmaster; Crazyhorse. We have individuals going to the scene, looks like *possibly* uh picking up bodies and weapons.
07:25 Let me engage.
07:28 Can I shoot?
07:31 Roger. Break. Uh Crazyhorse One-Eight request permission to uh engage.
07:36 Picking up the wounded?
07:38 Yeah, we're trying to get permission to engage.
07:41 Come on, let us shoot!
07:44 Bushmaster; Crazyhorse One-Eight.
07:49 They're taking him.
07:51 Bushmaster; Crazyhorse One-Eight.
07:56 This is Bushmaster Seven, go ahead.
07:59 Roger. We have a black SUV-uh Bongo truck [van] picking up the bodies. Request permission to engage.
08:02 Fuck.
08:06 This is Bushmaster Seven, roger. This is Bushmaster Seven, roger. Engage.
The official report also comes to the conclusion that they were engaging the van because it was picking up wounded insurgents. Of course the wounded man wasn't an insurgent but one of the journalists.
http://www.collateralmurder.com/en/transcript.html
https://www2.centcom.mil/sites/foia/rr/CENTCOM%20Regulation%...