Earlier quoted context omitted.
So obvious right? Well, we already have laws that make the possession of heroin illegal. They are broken all the time. With regards to the original point about silly laws that prevent us from spending our money and free time in ways that don't harm others, if person A is walking down the street and person B illegally uses heroin on the same street, person A is not likely to be harmed. You can't really say the same ab…
You have established that person B is not going to follow the law in any case. So if there is a law in place preventing person B from possessing a machine gun, person B is still going to acquire a machine gun and use it illegally and person A is still harmed. You haven't solved the problem by moving the solution further up the chain, but you have prevented responsible, law-abiding folks from acquiring a machine gun.…
That does not mean that someone who really wants a machine gun cannot get one - but that it takes a lot more effort to get one. Effort that many deranged and unstable people are not willing or able to dedicate the effort to see to fruition. Even in the age of anonymous online exchanges gun import rates are puny compared to firearm availability in the US.
I think it is sound psychology to believe if you make it really hard to get something that an irrational actor will be less likely to pursue destructive behavior. The difference between firearms and drugs is that drug users are recurrent customers and can form an underground economy, the sociopath with a machine gun is often a one time shopper. Seems more economics than anything else as to why it is more infeasible to maintain a firearms black market at scale comparable to the drug market, regardless of ethics.