“Kei modernized their truck”.
Kei is a style of vehicle. This is like saying, “pickups modernized their truck”. So let’s try and understand what this misguided individual meant.
“The small vehicle that I saw had poor crash handling”. Perhaps, but that’s going to be on the individual vehicle, not a class, in the same way some small vehicles handle really well, and some fall over (remember the Mercedes A class, anyone?)
“The style of vehicle that is categorised by kei is impossible to secure, and all of them score zero”. I’d love to see evidence of this, if you’ve got any. A modern kei-style car, the Honda E 2020 has a euro NCAP 4* rating - not the best, but not zero, and that’s just the first one I found.
Sadly, kei trucks are not commonly for sale in the UK or US, so I can’t find ratings for them. There’s no reason they can’t be made as safe as other small vehicles, only a market preference for larger vehicles.