A fear of doing something terrible, rather than the action. Not to say that such action is impossible, but rather, the emphasis is on vividly, tangibly confronting the hypothetical and real possibility, as a possibility. LSD is extremely potent, such that the thought of it being available at the corner quik-mart is unthinkable. It is better to let people endanger themselves and others to some large degree, rather than attempting to have big brother protect us, and rob us of self-responsibility and freedom. Life is dangerous.
Freedom is dangerous.
We should not neurotically try to eliminate this danger by eliminating freedom. However, LSD is dangerous. I have a philosophical hypothesis that the worst danger of LSD is the danger of having a divine insight about the shaky foundation of morality, and feeling forced, in the name of Truth About Morality and Self-Control, to wield the sacrificial knife on an innocent person. The theory of religious sacrifice is an interesting area of current philosophical research. Jehovah, the god of Truth and Justice.