Although this sounds a bit callous, it does appear that most drivers were going too fast for the conditions and were unable to stop in the distance seen to be clear.
Well I was on the M5 that night (visiting the Bridgwater Carnival) both before and after the accident and there wasn't any Fog in the area. Something not mentioned is that traffic was very heavy due to the carnival and indeed at some point was at a standstill on the motorway approaching the junctions for Bridgwater.
But the accident was after the carnival on a northbound carriageway, south of Bridgewater, I would think the traffic would have by this time been busy heading Southbound.
My brother at the time of the accident was working in the Sainsburys adjacent to the rugby club/ crash scene, and he said the fog was very thick that evening.
I feel the organiser was being used as a scapegoat, and I agree with the court, if it has never happened before it wouldn't be considered an issue, and you cant prosecute in hindsight.