When I riding I became familiar with the Snell ratings (I think it was Snell 85 at the time).
There was also an Australian Standard for helmets - which, like the US was required for helmets sold for road use - and the choice was relatively easy because most (recognisable name brand) helmets carried both.
Looking at the NYT article I think I would have to agree with the concern on excessive rigidity.
I always considered the helment to be a 'one hit wonder' (after one hit you wonder if it will protect you again
). After that first hit it became the spare for the pillion ....
LoBelly