Benn, I agree.
I know the intentions are sincere, and if we assume prohibition is rational then the intentions might even be ethical.
But really, we are hiring nurses to supervise people  injecting themselves with what we know beforehand is not the drug they would like, but instead carfentanyl strong enough to kill an elephant. 
Allowing these voting consenting  adults to buy graded measured adulterant free drug, just like I can buy bourbon or merlot is where we must be headed,