Yeah I don't know what they issue is or why NB/MW have selected a product clearly posing an unreasonable risk of injury through normal use.
What is the unreasonable risk of injury? Glass breakage? That's no different than any glass carboy. And, while I no longer use glass, lots of people prefer it.
With these particular glass fermentors there has been an unusually high number of complaints about the glass cracking or breaking even from people who use other glass carboys. Apparently the glass is much thinner and some people have had them break just by placing them on the ground. It isn't just the use of glass but the use of glass that does not seem well designed for this purpose.
I have also heard that from an engineering stand point they are not structurally sound. The large opening removes much of the rigidity that the bell on a carboy provides. I'm not an engineer, so don't quote me.