I don't see the origins of addiction relevant to arguments about containing current addiction when it moves to the illegal market. But I agree that supply-side targeting when talking about legal industry makes a lot of sense. Being legal, they also have lobbyists, which reduces the impact, same as other legal drug suppliers.
> If violence is coming from addicts and not from suppliers
Others have mentioned this, but opiate abusers don't get violent when high. Some small percentage sometimes get violent when they run out of money to score. Experiments elsewhere suggest that it is a lot cheaper (in money and in human costs) to contain, (in some way) legalize and (if they want it) help them get clean then clean up after them.