I understand his point. I just disagree with much of it. Something squishier and of a similar thickness won't slow the head/brain (absorb very much energy) much before it stops it. He also thinks using eggs is a proper test - somehow missing the major point that the mass of an egg is so much less than that of a human head. Whether an egg shell cracks or not isn't a particularly good model for evaluating head protection. Nor is pressing your thumb against some Styrofoam. His arguments against EPS are weak. He seems to misunderstand the issues around absorbing energy which is the key role that EPS plays.

The design problem for bicycle helmets is hard. How do you add useful protection in a lightweight design? Well, the fact is that you can't do it very well. There are some basic physics issues involved that are very hard if not impossible to get around. Automobiles manage the forces by having large crush zones and spreading impacts over larger areas of the body. (They also use EPS in their bumpers and other places for energy absorption). A large crush zone on a helmet would be unwieldy. Who would use it? And it is no wonder that football helmets don't use EPS. The helmet needs to withstand repeated impacts. EPS is useful one time. But motorcycle helmets use EPS as the primary material for impact energy absorption. He's simply wrong to assert otherwise. He also seems to think that rock climbing helmets don't use EPS, but they often do. Likewise, EPS is commonly used in horse riding helmets. I could go on.