That is the “legal, but with regulations, make it not bother anyone else” part.
Illegal simply means that if you have/consume said substance, there would be legal consequences (fines, imprisonment).
These restrictions and rules of use don’t make the drug itself illegal, they just make it illegal to use in certain scenarios.
wouldn’t you need to do ‘hail sized pea, hail sized baseball’ etc? otherwise you are comparing the size of hail to other objects, rather than other objects to hail