No one said cargo vans don't pose any risk at all. Clearly they do. But so does a Toyota Corolla. The same tree-plowed and flipped cargo van above could have been a Dodge Caravan or a Ford Explorer or a Honda Prius and the results, and the risk, would be the same to the general public.
It's not about zero risk, it's about unreasonable risk. Heavy trucks and buses, and vehicles carrying HAZMAT, pose an unreasonable risk to the general public. Cargo vans, and RVs, certainly post a risk to the general public, but it's not an unreasonable risk or even a greater risk than the general public already poses to itself. The FMCSA doesn't keep track of non-CMV accidents, but the DOT does, and they have a separate category for vans and light trucks, a category for each vehicle type, specifically to keep track of the accident and injury rates. They do this for several reason, not the least of which is to ensure manufacturers are complying with safety regulations, and so they can identify any unusual uptick in accidents of a certain vehicle type.
If cargo vans or RVs had a higher rate of accidents and injuries than that of the general public, they would be regulated and/or require special licensing and training. The public would demand it. When a cargo van or an RV has an accident, it's a mess, but it's not any more of a mess or the injuries any more severe or numerous than that of any other general public accident. Unlike, say, a big truck where the accident is devastating and nearly everyone except the driver is killed. If cargo vans or RVs killed nearly everyone they came in contact with and the drivers walked away, the public would demand regulation of those vehicles.
Currently, cargo vans and Corollas and Winnebagos pose the same exact risk to the public, so there is no valid reason to single out cargo vans and regulate them. None.
It is interesting that, with very few exceptions (the exceptions being mostly people who work in Safety departments of large carriers so that their jobs would be easier if every vehicle had to follow the same rules), the only people who are advocating the regulation of cargo vans to log and scale are people who coincidentally are required to log and scale. They always say it's not because of jealousy, yet they can never come up with a valid, reasoned argument for regulating cargo vans. Their arguments are rife with classic logical fallacies, usually one where they cite an extreme example to try and prove the rule, and go, "See! See! See!" It's interesting, because if you apply the same logic, then all station wagons would have to be regulated because of Clark Griswold.