A quote from Timothy Leary: "I give the CIA total credit for sponsoring and initiating the entire conciousness movemenet, counter-culture events of the 1960's."
As for why synthetics are dangerous, I think there is a thesis paper waiting to happen on that. Mostly because I don't think we fully understand the effects in total of some drugs. For example, I had friends the VA was trying to put on synthetic THC... but every single one of them said it was horrible, and I came to the conclusion that THC(a/b) alone is bad and that it's the natural combination of it and the other 300+ cannabinoids, including CBD, that really show promising medical benefits.