Anecdotally, DMT made me black out and go crazy for 20 minutes. I would not make it easily available.
These drugs should be treated as seriously as any other (know your drug!). Some will fail to do that, but that is how it goes.
The moment I hear "drug X caused this bad thing to happen" I think of how much suffering alcohol consumption does globally on a daily basis. That tempers all associated concerns.
Until you compare the number of sufferers as a percentage of users, there is no tempering of concerns here.
I've seen multiple studies, mostly looking at pills sold as MDMA, which examined the actual content of samples of street drugs, and the findings were not exactly surprising - almost all samples were not pure (I mean, aside from cutting agents!) MDMA, often containing significant amounts of amphetamine.
In a legal, regulated marketplace, there are guarantees of quality, which would represent a huge increase in safety for drug users.
With a legal marketplace, production would also shift from global cartels to local businesses - improving lives, creating local jobs and increasing tax revenues.
The fact is that there will always be a market for drugs - people have afterall used drugs for millennia - so why not accept that and try to make something better of it?
There are of course risks to taking any drugs, just as there are with alcohol - but the potential for good by legalising is staggering.
The most profound thing about DMT was learning that what I saw decades ago is a shared experience: https://en.wikipedia.org/wiki/N,N-Dimethyltryptamine
For actual learning, LSD/Psilocybin is a much gentler teacher.