How anyone can be so stupid I do not know. The gold standard for evacuating an aircraft is ninety seconds because - unless you're lucky - that's how much time you're likely have before the plane catches fire or explodes - and when the cabin is already filling with smoke it's a fairly reasonable assumption that either or both of these things might happen as in fact they did within minutes of this plane crashing.
Obviously these idiots are special little flowers who don't bother to watch the safety briefing or read the safety information because it won't happen to them. But it can and in this case they and the others they obstructed were close to losing their lives.
There are reasons for not wasting time getting your baggage. First is the obvious time constraint but then there are the equally obvious dangers that hauling bags with you can cause. You could hit someone as you pull it down knocking them unconscious and blocking the passage way - and if you don't think this could happen, I've seen enough near misses when people are rushing to get off without it being an emergency to know this is a real possibility. But once you have your luggage what can happen next is even more disturbing. Bags can catch on seats even during an orderly standard disembarkation - aircraft aisles are narrow after all - and when people are panicking in an emergency it's even more likely that it will obstruct the aisle blocking others from getting out. Then there is the danger that bags can catch on the evacuation slides, tearing them and rendering them useless. As well, how do you use the slide appropriately if you are clutching a piece of baggage. You risk broken limbs or worse for yourself and harm to others using the slides.
I understand why it's hard to leave your valuables behind but surely your life and the lives of those you are blocking are more important than material things. If you're worried about losing important documents why not keep them on you in a waterproof pouch (planes do sometimes come down over water). Then you'll have them with you at all times - and keep a USB stick with irreplaceable information with them as well. That's simply common sense and it won't matter if your laptop gets left behind and destroyed.
And just one other point - cabin crew are not just glorified wait staff and ticket checkers. They are highly trained to keep you safe both in the air and in any emergency. It's their job to get you off a plane as quickly as possible in an emergency and they know what they are doing. They have to learn to cope with all possible crash scenarios and their training is rigorous and on-going. You ignore their instructions at your peril in a disaster situation.