I don't see why Psychedelics should be singled out. Decriminalisation of all drugs makes sense for a multitude of reasons. The primary reason - drug abuse is a health issue, not a criminal one.
Fair enough, if someone commits a crime due to being under the influence of something or to fund their addiction then let them be charged for that crime. Otherwise, no criminal action need be taken. Drug addiction and abuse is a huge problem, and should be tackled with help and treatment to sufferers. We've already seen hundreds of studies that show the alarming link between depression/poverty and drug abuse. If you're interested, type in "the rat park drug experiment" into Google.
If you want to go further and question whether we should have some sort of legislated supply of drugs then there are plenty of arguments for that also.
Historically, prohibition has proven time and time again to be ineffective. It is unworkable. If there's a demand, there will be a supply. Humans are drawn to experiencing new things, this has always been the way and it always will be. Humans are also susceptible to mental pain and torment, and as has been seen throughout history we will quite often search for a relief from this hardship. Naturally, there's always going to be people out there looking to take advantage of this supply, as I'm sure most of us he know!
Right now, many of these people are violent criminals earning huge amounts of cash tax free. Their products are often cut by insane amounts of God knows what, or in many cases they are selling something entirely different.
The ban on drugs has of course created the grey market, labs are discovering more and more new unknown chemicals every day. These easily skirt around the law by being sold with labels such as "not for human consumption" etc... and lets be honest, quite a lot of them we know very little about and are very possibly dangerous.
Most MDMA related deaths this year? Cause - PMA. Absolutely mad, huh? Most deaths due to MDMA don't even involve MDMA. Most LSD related deaths this year? Cause - NBOMe. Same story. Two drugs with a huge history of use and a high safety profile are now fairly dangerous unless you have a test kit. The scary thing? It's too late now. These drugs have gone mainstream and are frequently sold by black market dealers claiming that it's the relatively safe original.
The list goes on and on, and it will continue to go on. There are so many new chems out there now it's fucking scary. It's shocking how nobody foresaw this happening all them years ago when the War on Drugs began. I mean, surely with the influx of new drugs at the time they must have had some idea on what was possible?
Now, I'm not saying lets go open a fuck load of shops that sell drugs legally. There are so many potential complications and things to consider. I'm not even completely sure on the idea. This would have to be a strictly controlled market, and certain deadly drugs simply could not be sold. But there are definitely some relatively non toxic stimulants, sedatives, dissociatives and psychedelics that the legal sale of, while not ending drug abuse, could ensure that people stay clear of more dangerous alternatives, in addition to giving users a 100% guarantee of what they are ingesting.
Criminal sale of drugs would obviously fall dramatically, while the money brought in from taxation could be used to fund research into the treatment of depression, the number one cause of drug abuse. Obviously if such a radical change was introduced (I realise I'm dreaming here) there would have to be an emphasis on education and the potential dangers of drugs. Not the sensationalist nonsense of the past, but not a laissez faire attitude either. Just the facts coupled with a hardline approach to safety and harm reduction. By no means should this education encourage or glamourise drug use, something we can all be guilty of.