At ~800g AUW, sub-250g requirements just put the nail in the coffin - the avoidance tech doesn't scale down - a 2kg drone need the extra same weight in sensors and compute and battery to power that extra compute as a 249g one.
There is a country what happily used DJI drones to harass their own people for years, and now happily use them to kill them and not only them.
Even the EU is at best a loose (and obviously voluntary/ephemeral what with the UK) collection of generally aligned states.
Same thing is happening with high quality cameras, Im sure GoPro is not happy, and neither is Blackmagic.
It seemed more like a ‘eh good enough’ guess based on the amount of damage someone could actually do while staying under half a pound. (If crashed into someone/ingested into an engine, ran into a car on the highway, etc.).
Similar to DMV licensing cutoffs. A lot easier to get a license to drive a scooter than a school bus or hazmat tanker.
There isn’t even a medical requirement!