So when some guy gets crushed to death by an HGV and some idiot with sponsorship from a helmet company says "If only had been wearing a 300g foam hat when 10 tons of steel drover across his head and torso!"...
That's just hysteria. Please direct us to an example where this has actually occured. I don't think I've ever hear anyone, including employees of cycle helmet manufacturers, intimate that a cycle helmet will save you from death or serious injury if a lorry drives across your head.
Sorry - you are wrong. Doubly wrong in fact. But, hey - you're used to it!
1. Helmet companies and their lobbyists promoted the "90% of deaths can be prevented by helmets" claim for years - which came from a study that Bell sponsored and which is now completely discredited. You can't get that rate without saving people whose heads have been driven over by lorries.
...You can't that get that rate without helmets doing something that you have to be an even bigger idiot still to believe: 50% of cyclists who die have fatal toros injuries, so you won't get that 90% save rate unless helmets protect torsos!
..You might not have been bright enough to work out that this is a claim that helmets make cyclists lorry-proof - obviously you weren't, perhaps because it would involve actually knowing stuff (admittedly stuff that's in the thread, so that isn't much of an excuse) and being able to do sums - but it is. No, don't thank me!
2. In fact Bradley Wiggins made such a claim a couple of weeks when he said that the death of a cyclist crushed by a lorry proved that helmets that helmets should be made complusory. (And yes he is sponsored by a helmet maker.)