Repack - a complex question. Very complex.
On a moral front and taking it simply I don't believe in a victimless crime. Many drugs don't affect anyone but the person taking them. Many of the ill effects of drugs are due to the illegality rather than the drugs.
However most drugs are made/ grown or imported by "organised crime" thus buying drugs puts money in the pockets of the criminals.
I'll use cocaine as an example. To the individual it does indeed incur a health risk. Risks of cardiovascular disease are increased and prolonged or heavy use also can cause mental health problems. Then there is the geopolitical issues. The amount of money that cocaine production generates has very undesirable effects on the producer countries. However these effects ( corruption of local officials etc) are in reality a consequence of prohibition rather than of the effects of the drug itself.
Any discussion of this sort of area is going to be contentious and I think you need to look at each drug individually rather than consider them all the same. You also need to consider the effect of the drugs themselves and the effects of its prohibition separately rather than consider them the same.
The actual effects of drugs tend to be mainly on the individual. The effects of prohibition tend to be very damaging to societies.
Using heroin as another example. a large % of "petty crime" in this country is from junkies getting the money to pay for their fix. Without prohibition this would not be the case. Remove the prohibition of heroin and you reduce crime significantly overnight. You would also reduce the health risks to the consumers. would removing prohibition increase the number of users? This is an unknown really but in my opinion it would not. the experience of countries where prohibition is less strict would seem to back this up but it would be a leap in the dark.
Take cannabis. Most cannabis consumed in the UK now is produced in cannabis farms run by organised crime. This is putting money into the hands of undesirables ( to say the least) However again this is a result not of the drug but of the prohibition of it. actual cannabis consumption causes little damage to individuals and society ( but by no means zero)
So to consider the moral implications of drug use I believe that you need to separate out the implications that come directly from the drug use and those that are effects of the prohibition.
Consumption of drugs on an individual basis in our current system certainly carries some immoral aspects in that you are helping cause corruption of and damage to societies, but removing prohibition would remove much of this. However unless demand is curbed this will continue and as mankind has always used drugs in one form or another then I see little chance of reducing demand thru the criminal justice system. Prohibition simply does not work and indeed may be contributing to the damage to societies
While demand is there then someone somewhere will produce to meet that demand. Until demand can be reduced then there will always be production with the damaging effects this illegal production and distribution causes on societies around the world.
Different drugs have different effects on both the individuals and societies and should be considered individually. What is right for MDMA may not be right for cocaine
My own view is that prohibition is more damaging than consumption. As a purely pragmatic take on it then I would remove prohibition and take drug issues from the legal / judicial sphere into the health sphere. I am sure this would cost the country less and reduce the damage in producer countries. Legally produced drugs can be controlled and taxed and these taxes used in health promotion / harm reduction.
Its a hugely complex issue and this post is only intended as a series of discussion points and is not intended as any definitive set of answers