An attorney doesn’t go after anything that doesn’t have a source for a payout; Attorneys are only interested if there something to take.
If uncle Bob teaches little Frankie how to scuba dive and Frankie croaks diving, who sues uncle Bob for his trailer and his pot that he doesn’t have to piss in?
The problem there is that recreational diving seems to cater to a graphic that skews a bit affluent. There are exceptions, but many have something to take. People without a pot to whiz in don't buy a lot of plane tickets to Cozumel and Bonaire, dive gear, etc...
I'm a fan of small government and minimizing liability risk. That said, as others mentioned, with skiing and surfing, the untrained can have a fair idea of the risks. With free diving to a point, though shallow water blackouts isn't common knowledge. With scuba, we've got 'don't hold your breath,' nitrogen narcosis, potential risks of dealing with highly pressurized air and other problems that aren't evident to the average Joe without some education. Therefore, the presumption of risk awareness leading to informed decision-making is a harder sell with scuba diving.
I get it, some people seem to think the world ought to be bubble wrapped and everybody mollycoddled. That said, at least an OW course so they have some idea what they're getting into seems wise.
Even then, how many OW grad.s know about immersion pulmonary edema? IIRC (it's been awhile), the Rescue Diver course covering lung over-expansion injuries more than OW did.