As far as the social problems with psychedelics, they're pretty minor compared to the effects of alcohol, tobacco, amphetamines and opiates (all drugs with various degrees of legality). A lot of the problems stem from consumer mentality across the board, i.e. advertisers have indoctrinated people with the 'more is better' mentality. Probably the most anti-consumerist sentiment ever expressed is 'Less is More' but that's then mentality anyone contemplating experimentation with psychedelics should adopt. The dose-response curve is more exponential than linear or logarithmic.
Incidentally, the psychiatric therapy models tend to involve a single relatively high dose in a controlled setting. This is entirely unlike the current (and much more profitable) pharmaceutical regime of daily dosing with antidepressants or amphetamine derivatives. Likewise, psychedelics have shown vast potential for helping people break free of addictive disorders involving alcohol, tobacco and opiates. Again, this is an unprofitable model for the pharmaceutical and recreational drug industries, who rely on the heavy users for the majority of their profits.
Finally, psychedelics have the interesting effect of distorting sensory perceptions, and if you can't necessarily trust your sensory perceptions, this has a knock-on effect - you might also start doubting things like the validity of government propaganda or the reliability of media publications or the pronouncements of the religious authorities. This can be described as an 'anti-brainwashing' effect - and such independent thinking can be a threat to established power structures in human societies. People who believe that unquestioning faith in authority figures is the cornerstone of social cohesion (aka authoritarian control freaks) are thus very alarmed by psychedelics.