Ultimately the issue was massively compounded by the drivers themselves. The early crashers simply weren't looking where they were going as the big cloud of smoke should've brought them down to walking pace (the camera guy managed to see it and stop in time, why didn't the others?), along with parking in daft places. If you park before the accident, you're more likely to become the next accident: You really should always try and drive past it to park up. That said, in this case that would've meant the guy would have had to walk even further back before he could start flagging cars down, so a lose/lose scenario really.
The ones that panic and just mash the brake also contribute here. If they'd stayed calm and in control, they could easily have slowed down and driven around the obstruction. It's poor driving all round.
And despite all that, it just shows what a seriously dangerous place the Ring is. Also, it's why I'll never do a TF day there unless the car is 100% sacrificial or as insured as I can reasonably make it.