The problem is that you can only do that if you know the outcome of the crash is going to be ok - so you are looking at this incident with the benefit of hindsight and saying "look, it all turned out ok, they could have taken their bags" and yes, it probably would have been.

Unfortunately, during any aircraft crash at any actual moment, you have no idea how long you have to get everyone out. As someone else has calculated, everyone taking just 3 seconds longer to evacuate means it take 7.5 mins for everyone to get safely off the plane - and your unknown variables in a crash are things like how long will it take for the aircraft to fill with smoke/water/fire?

It's not acceptable in a crash for anyone to attempt to do anything which is a) unnecessary and b) increases the risk of death for others on the plane - even if they are in shock. Arguing that such behaviour should be allowed, when during an incident you don't know what window of opportunity you have to get everyone off the plane before something catastrophic occurs is frankly playing russian roulette.

I'm thinking of the Airbus which caught fire and burned out in the far east with pax on board - was the entire plane not ablaze in around 3 mins? If you've got people trying to get bags off in that kind of situation, then they will kill some of the people behind them, unnecessarily.