My opinion: Thanks to the USA govt of yesteryear, hallucinogenic drugs are incredibly underestimated as a tool that could be used for the benefit of mankind.
The potential these drugs have to give us knowledge about the brain, personality, nature/nurture, socialisation, psychiatric disorders and just the human condition in general is enormous. But almost all research with these drugs has been cut off since the late 1960s/early 1970s.
I don't think it's right to view hallucinogenic drugs as drugs which have no medical or social benefits. The state of suggestability that such drugs provoke can be used in an enormous number of ways, from treating and learning about Disassociative Identity Disorder (formerly Multiple-Personality Disorder), Obesssive-Compulsive Disorder, phobias, depression. The fact that such drugs appear to 'strip away' socially conditioned responses to stimuli is a total social goldmine to those smart enough to recognise this, because this give us insight into why people are like they are and how behaviour can be changed or modified.
Furthermore insight into the human brain and human condition has multiple applications in terms of politics, conflict resolution, class conflict, identity issues, in-group and out-group bias, violence in society, groupthink and, more generally the social evolution/social trajectory of humanity. On a smaller scale, this all undoubtedly has valuble uses in domains as widely removed from each other as business, prison reform, education, parenting, and so on.
It is beyond my comprehension why there is such heavy handedness on research with these drugs.
I'm not saying everyone should be able to buy mescaline at their corner cafe, but for controlled research purposes at least these drugs should be widely studied with few limits.
I'm amazed how drugs like Prozac and Ritalin and certain barbiturates and some stimulants like psudoephredrine are happily passed out, often without prescription, without a second thought. Yet thanks to the government-sanctioned profit-making behind these drugs, we don't tend to view these drugs as the 'bad' ones. IMHO, these sorts of drugs have more in common with the real bad drugs like cocaine, tik and cat. In fact, the latter two are manufactured from commonly available flu and diet drugs. They make crystal meth from a flu drug, yet a hallucinogenic drug that prompts intense self-inspection is the 'bad' one. Ridiculous.
I'd sooner give my kids magic mushrooms than Ritalin, which is basically cocaine as it works off the same receptors but just uses different 'keys' to unlock those receptors.
The drug companies and government are pulling one over our eyes here, and we should wake up.