I don’t think it should be banned or licensed but education safety needs to be promoted. Everyone should need to view safety training courses before purchase. Water washable resin does NOT mean safe!!!
I do not think children should be allowed to use this technology it’s too dangerous. I see too many posts with people using them in small apartments. No parent would dream of allowing children to play with gasoline, but washing 3D prints in IPA with nasty dangerous chemicals “appears” to be OK with some parents.
If you want to print interesting fun objects with children then FDM printers are much more suitable.