I grew up in the northeast. Abrupt and unpredicted snowstorms are common, and some of them are dense enough to drop visibility laughably low - 10-15 mph would offer visible stopping (and be a fairly acceptable speed for a crash regardless). People don't want to take six hours to get home, so they keep driving. If the roads are decent, they keep driving at ~30 mph or faster to make decent time.
So now you have a situation where all the other drivers are exceeding their visibility. If you drop down to 10 mph, you get to be the obstacle they hit at >30 mph when you loom up out of the snow!
The result is that everyone goes 20 mph or faster, because everyone else is. Yes, that's stupid and dangerous. No, there isn't any 'safe' behavior available if you get caught out on those highways.
- Don't live in the northeast.
- Don't drive in bad weather conditions.
- Don't organize your life around automobiles such that you can't manage daily life without one.
All I can really say is that I've definitely been on the road at moments where I realized that 100% of my options were dangerous accident risks. At that point you mostly try to minimize likely crash speed (if everyone goes 15-20 on a divided highway, probably no one will die) and look for an exit.
Fog is tricky. Fog can give the driver a false sense of security. Modern overly-reflective road markers can, at night, make a driver think they are seeing further through fog than they are. They can see the lines, but can they see the black car parked ahead? Note too that large pile-ups in fog often involve trucks. Imho much of that is because truck trailers have poor running lights. We see the cars ahead. We follow their taillights through the fog. But that black truck flatbed trailer with two tiny red orbs is invisible. Or we think it is further away.
Fog also thickens unevenly. It blows around. Slamming on the brakes immediately upon entering a bank isn't going to make you any friends amongst the people behind you. That truck 4 seconds behind you (a reasonable distance on a highway at night) might not stop as quickly as your ferrari. Truck drivers are also much higher. They may have greater visibility than you and not realize that your sports car places your eyeballs in the low-level fog. The safest bet in traffic is generally not to act abruptly and unexpectedly.
(fyi, a sportbiker's helmeted head is also generally much higher than in cars, even SUVs. They too have better visibility in fog.)
And if you forget to turn on your car's taillights, all is lost. There is a reason that motorcycles have them hardwired on.
In the real world pileups typically happen when you suddenly go from full visibility to dense fog (or snow) with no warning.
So maybe instead of blaming people who could not do anything about it, see if there is a way to help them.