I know tobacco laws in this country (USA) are archaic. It seems like this ties into tax laws more since tobacco regulation and taxing is determined by locality. And by restricting federal handling they can push this closer to the localities instead of a federal blanket of laws
Also notice this line; "...aerosolized solution, delivers nicotine, flavor or any other substance to the user inhaling from the device.”
They know it might be used for cannabis. It's just like how non-alcoholic beer falls under alcohol regulations even though it should be treated like normal beverages. Good examples of old laws not properly reflecting the current times